DMA reverts to PIO

Wed, 2007-07-11 08:30 by admin · Forum/category:

The stuttering DVD drive or the lame hard disk

Table of contents

for this article

Quick solution

This is the recommended solution. If you're not interested in the details, but just want to fix this problem as quickly as possible:

  1. Internet Explorer: click, Firefox and other browsers: right-click here.
  2. Internet Explorer: Despite any warnings click on the [Open] or [Execute] buttons as required to execute the file resetdma.vbs.

    Firefox and other browsers: Save the file resetdma.vbs to your hard disk. Double-click on the file in Windows Explorer and allow it to be executed.

    (If you fear that this web site could be malevolent, you could use the manual method instead, which is described below. You can also download, save, and inspect the program with an editor like the Windows Notepad. It is a script text file.)

  3. If the program found any ATA or SATA channel to reset, reboot your computer and test all drives.
  4. If the problem is still not solved, set the offending channel to PIO manually, reboot your computer, set the channel back to DMA, and reboot again.
  5. Please report your results here. Thanks!

Please note that this works only with the Windows drivers. If your device had its own manufacturer's drivers installed, this program cannot fix the problem and will not do anything to them. Instead it will report that no resettable DMA channels were found.

Note also that many CD and DVD drives only use UDMA-2, because their data rate is much lower than that of a hard disk. This is normal and no reason to worry.

If you are interested in the details, read on.

The program tries to reenable DMA in the registry exactly as described below, for all suitable (S)ATA channels. Windows then redetects the DMA status after the next reboot.

If you use the program again after a short while, it may again report that it has reset the channels. This is normal behavior and not a sign of any problem.

General description

This article also applies to Windows 2000. (Peter Frank reported successful application on Windows 2000 with Service Pack 4.)

DMA is an abbreviation for Direct Memory Access, an access method for external devices where the data transfer is not done by the central processor, but by a small special processor called DMA controller. It uses a procedure called cycle stealing, where the central processor memory access cycles are delayed for very short times to intersperse DMA controller memory access cycles. Some newer, faster DMA modes are called UDMA (Ultra DMA).

The alternative, slow and inefficient data transfer mode is called PIO, Programmed Input-Output, where the central processor transfers data byte for byte or word for word. This requires many processor commands for each data word and therefore causes a high and unwanted processor load.

A typical symptom of PIO mode is slow data transfer, accompanied by high processor load, leading, for example, to a choppy video display.

Possible causes for falling back to PIO mode

The most frequent use why a CD or DVD port falls back to PIO mode is a scratched or otherwise unreadable CD or DVD. For example, some newer DVDs, initially from Sony, carry a copy protection scheme that relies on defective sectors. If you try, without using special software, to copy such a DVD (which doesn't work), then this can already trigger the problem.

However, there are a few reasons why a computer may use PIO instead of DMA, particularly when it's the hard disk port that falls back, not a CD/DVD drive port. For example, David Duberman reported in 2005 that some Dell computers have DMA disabled in their BIOS by default for the second hard disk. So it is a good idea to check the BIOS settings first.

2007-05-13 – Jason Paquette confirmed that the BIOS setting in his Dell computer was wrong too and prevented DMA mode. Correcting the BIOS setting immediately enabled the DMA mode.

A not so rare hardware problem is a bad or too long IDE data cable. You need 80-way cables, not the older ones with only 40 wires. With poor cables the device may work, but Windows will probably step down to lower DMA speeds or even to PIO.

A further cause may be waking from standby mode, if one of the involved components does not perform this process correctly.

2007-02-20 – Stefan Welte wrote that on an Elitegroupsystems K7S5A computer all IDE hard disks ran in PIO mode, because automatic device recognition was disabled in the BIOS. (The computer booted from a SCSI disk.) Enabling device recognition solved the problem without any further measures.

2009-06-27 – markvm confirmed again that the BIOS in a Dell computer prevented DMA mode. Please see his comment below. In his case a hard disk was not recognized by the BIOS. After enabling and starting the automatic recognition, everything fell into place nicely, and DMA was automatically enabled by Windows.

2009-11-19 – flemur13013 mentioned again in this comment that setting the disk recognition to "Auto" in the BIOS settings solved his problem of a slow, CPU-gobbling secondary hard disk.

Occasionally a chip set or controller driver is buggy, so check with the manufacturer for updates.

2007-03-01 – Francois Eraud reports one such case in a Sony laptop, regarding an ALI M5229 chip set controller, solved with driver version 4.008.

2008-03-30 – Arran located the elusive drivers for this ALI M5229 controller chip. Please read his comment For those with the ALi M5229 IDE Controller in the comments on one of the next pages.

Other reasons can show up in the event log, so check this first and see if you can find repeated Atapi errors recorded. If so, you likely have a hardware defect. You can use the procedures described on this page, but your computer will probably fall back to PIO mode again and again, until you solve the underlying problem, which may be located inside the device, on the motherboard, or in the IDE data cable and its connectors.

A dramatic example was reported on 2006-12-29 by David Hähningen:

If you (half asleep in the dark and with considerable force) try to put the ATA plug on the hard disk the wrong way around, the gap called "KEYPIN" (pin 20 on the plug) pushes pin 21 of the hard disk socket and bends it aside. (This pin is responsible for DMA requests of the hard disk.)

As the disk can no longer reach the host with its requests, there is a communications problem, and Windows XP switches into PIO mode. A blessing in disguise: You can still save the data, though slower than usual. ;)

Few will succeed in repairing the disk. Just pulling the pin straight may not quite cut it, as the connection to the printed circuit board is probably broken.

2007-02-07 – Carl Kaufmann wrote that he looked for a solution for a computer with an Intel chip set and found the Intel(R) Application Accelerator. As instructed, he first installed the Intel Chip Set Installation Utility, which already solved the problem (as observed in Task Manager). He went on anyway to install the accelerator. After that there was no longer any DMA/PIO choice in the controller options, but everything now works right automatically.

2007-05-15 – John Schumacher confirms:

I thought I was having this problem, but that isn't the case. My BIOS listed Ultra DMA as being disabled on all my drives. I looked for the Advanced Settings tabs for the IDE channels in Device Manager, but the tabs were no longer there. I ran Nero InfoTool, which confusingly listed DMA on for primary and secondary masters, but off for primary and secondary slaves. After doing some more searching, I found out that the Intel Application Accelerator I recently installed is the culprit. Running Intel Application Accelerator confirmed that everything was OK.

The Intel Application Accelerator can also have a quite adverse effect when it is run on an unsuitable processor. If in doubt, uninstall it and retest. (See the comment, Intel Application Accelerator by dkneyle = Ausie Davo.)

The trap

Windows contains a trap in which quite a few computers seem to get caught sooner or later. The trap was described in a Web article whose link no longer works (and also in another one mentioned below):

The crucial paragraphs are:

PIO mode is enabled by default in the following situations:
For repeated DMA errors. Windows XP will turn off DMA mode for a device after encountering certain errors during data transfer operations. If more that six DMA transfer timeouts occur, Windows will turn off DMA and use only PIO mode on that device.

In this case, the user cannot turn on DMA for this device. The only option for the user who wants to enable DMA mode is to uninstall and reinstall the device.

Windows XP downgrades the Ultra DMA transfer mode after receiving more than six CRC errors. Whenever possible, the operating system will step down one UDMA mode at a time (from UDMA mode 4 to UDMA mode 3, and so on).

Of course, drive firmware being quite complex and certainly containing programming defects of its own, it is not all that difficult to produce such errors. In my case a scratched DVD and later also an unreadable (overburned) CD did the trick, got the drive to choke and Windows to disable DMA for good. Later my hard disk hiccupped just once and also went back to PIO for good.

I had been using my laptop for DVD viewing for years, until I inserted a borrowed and heavily scratched DVD. The player and apparently even the DVD drive choked on it, and when I finally got the DVD to play, I found that playing was jerky and processor load was 100%, roughly half of which was system overhead.

This indicated that the drive had reverted from the usual UDMA (Ultra Direct Memory Access) mode 2 to PIO (Programmed Input Output) mode. No amount of resetting or changing the relevant registry parameters from 1 (try DMA) to 2 (force DMA) helped. Stubbornly the drive kept using PIO mode, and Windows even changed these settings back to 0 (use PIO only).

The following text will refer to the secondary IDE port because that is more often affected, but essentially the same also holds for the primary IDE port, to which the main hard disk is connected in most computers.

Before you begin to work on the problem, log on as Administrator or as a user with administrator rights.

Check Your IDE Port Mode

First check what mode your secondary IDE port is currently working in. Go to Device Manager: right-click on My Computer, select Properties, click on the Hardware tag, click on the Device Manager button, click on the plus sign to the left of IDE ATA/ATAPI Controller, double-click on the secondary IDE channel, click on Extended Settings and check whether it is set to DMA when available. Directly underneath that setting is a grey field that shows the actual working mode of your IDE channel. You want the highest possible DMA or Ultra DMA mode there, and you definitely don't want PIO mode.

If the Extended Settings tab is not there, perhaps another driver is used, probably from the manufacturer of the IDE ATAPI controller. You can still perform a simple test. In the Task Manager activate the option View, Show kernel times. Then put a high load on the device, for example by copying a large file, and check whether the kernel times are minimal (red line). If you observe considerable kernel times, roughly around half of the total load, then the device is running in PIO mode, which is bad. The whole purpose of the DMA mode is to relieve the processor (in kernel mode) of this load.

Assuming the Microsoft IDE ATAPI driver, normally you don't have to use the registry editor, because the normal settings are also available through the properties dialog for the IDE port, but if you want to look at it anyway, the parameter for the secondary IDE port can be found through regedit.exe at


It is named Scsi only for historic reasons. Scsi Port 0 is the primary IDE port, to which presumably your hard disk is connected.

After trying various remedies—in vain—I found the abovementioned article and went to work again. I uninstalled the DVD drive in Device Manager and rebooted, but that did not help either.

So I searched for more and better information, then I went on and did the following.

Re-enable DMA using the Registry Editor

This chapter describes the manual way to do what the quick solution at the top of this page does automatically through a script program. If you're not interested in the details, you can back up to the chapter "Quick solution" above and run the script.

My thanks go to my fellow MVP Alexander Grigoriev who taught me this method.

Run REGEDIT. Go to the following key:


It has subkeys like 0000, 0001, 0002, etc. Normally 0001 is the primary IDE channel, 0002 the secondary, but other numbers can occur under certain circumstances. You have to go through these subkeys and check the DriverDesc value until you find the proper IDE channel.

Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether the device in question is attached as master or slave, but it can't actually hurt to delete both. Reboot. The drive DMA capabilities will be redetected.

Note that many CD and DVD drives only use UDMA-2, because their data rate is much lower than that of a hard disk. This is normal and no reason to worry.

2006-01-19 – Horst Schülke wrote that it is sufficient to empty the content of these values. But you can also delete the values entirely. Windows will automatically recreate them anyway, with new content.

Open Device Manager again and check whether the device is now actually using DMA mode. If so, congratulations, you've made it (at least until the next time Windows disables DMA). If not, you may have to change the IDE channel setting from PIO back to the highest available DMA mode and reboot again.

Many thanks to Tomáš Souček, Peter Götz, Alex Vaillant, and Cory Culbertson for piecing together the following information:

There are three keys that work together:


Each bit in these values means a transfer mode that the device may or may not be capable of. Somewhere at MS some of these bits can be looked up.


This is the actual mode the device is running at.


This entry may be the problem child. Peter wrote: "Normally not present in XP, it is created as a reaction to errors. This entry has absolute priority." However, there are doubts whether this is the absolute truth. It is still not entirely clear where this entry comes from. Erasing it or setting it to a DWORD value of 0xFFFFFFFF, rebooting, re-enabling DMA mode, and rebooting again seems to have solved the problem in some cases.


This entry contains the user's setting, manually entered in the advanced device properties. Has the same structure as MasterDeviceTimingMode. This entry appears when the user sets a limited mode manually, such as PIO only.

Another key that seems to create the problem is MasterIdDataChecksum.

All these parameters also exist for the slave drive as SlaveDeviceTimingMode, etc.

More information is needed. If you know anything, please click on Add new comment at the end of this article and write it down.

Alternative Method—Uninstalling the Port

1. Uninstall the secondary IDE port

Attention: Do this only if you use the Microsoft IDE driver that comes with Windows or if you have the driver on hand, because otherwise you may find yourself unable to reinstall the proper driver.

To uninstall the port along with its driver, open Device Manager as follows. Right-click on My Computer, select Properties, click on the Hardware tag, click on the Device Manager button, click on the plus sign to the left of IDE ATA/ATAPI Controller, right-click on Secondary IDE Channel, click on Uninstall. Deactivating is not enough.

Reboot to make the changes active and permanent.

After booting Windows will automatically reinstall the IDE channel and the DVD (or CD) drive. This Plug-n-Play process can take a little while, so give it a minute after the boot process finishes.

2. Check or reactivate DMA

But this may not always be not enough, because unfortunately Windows does not always automatically activate DMA on a DVD or CD drive. You have to check and, if necessary, tell Windows to try to use DMA first. It is possible that Windows XP with Service Pack 2 re-enables DMA automatically on reboot, but I have not tested this yet.

To re-enable DMA, go to Device Manager again. Right-click on My Computer, select Properties, click on the Hardware tag, click on the Device Manager button, click on the plus sign to the left of IDE ATA/ATAPI Controller, double-click on the secondary IDE channel, click on Extended Settings and change the relevant setting from PIO only to DMA when available.

On Windows NT and 2000 you now have to reboot a second time, but Windows XP applies the change instantly. Then you can go to the same place in Device Manager again and check whether the device is now actually using DMA mode. If so, all is well.

Note that many CD and DVD drives only use UDMA-2, because their data rate is much lower than that of a hard disk. This is normal and no reason to worry.

3. Driver is not intended for this platform

If you keep getting the following error message, please read on:

There is a problem installing this hardware.

IDE channel

An error occurred during the installation of the device. Driver is not intended for this platform.

2005-03-30 – Johannes B. wrote: The reason for this error is often that Daemon Tools or Alcohol 120% are installed. In this case the solution described below would not work. But when you uninstall these programs and then restart Windows, it will then install the device drivers without any further problems.

If these programs are not installed, then one possible way out is to rename C:\WINDOWS\system32\drivers\atapi.sys (or a similar path on your computer) to something like atapi.old.

If that's not possible, you can try it from the repair console (boot from the Windows install CD and select the repair console).

If Windows always automatically recreates atapi.sys, you can try renaming it in safe mode or from a command line window or you can try to rename or remove it in the driver cache as well.

Desensitize Your Computer's IDE or SATA Channels

There's a bit more to it. The following article offers a way to reduce the incidence of this problem, although it still doesn't solve it altogether.

IDE ATA and ATAPI Disks Use PIO Mode After Multiple Time-Out or CRC Errors Occur

Do read this article because it contains a useful long-term workaround. But you have to go through the procedure described here to re-enable DMA first.

Assuming you've done that, insert the ResetErrorCountersOnSuccess registry values mentioned in this article into both the primary and the secondary IDE port registry keys as described.

Unfortunately this is only a half solution, because when you enter an unreadable DVD, you will get 6 errors in a row, and the IDE channel will revert to PIO mode, but at least when you pull out the DVD in time and then insert a good one, the error counter will be reset and it will at least be a bit more difficult for Windows to hobble your IDE drive.

A little warning: One user reported that by mistakenly putting the value into the parent key, rather than into one of the 0000, 0001, 0002, etc., subkeys, he was accused by Microsoft's Genuine Advantage check of using a pirated copy of Windows and therefore denied online updates.


Useful info on re-enabling DMA. No more jerky video from primary slave! Thank you

Thank you for a very helpful article. After applying your fix I saw a 10x speed improvement!

Don't mention it!!! After months of trouble-free operation, DVD playback suddenly started to crap out on me, and your site was the only one I could find that remedied this problem. I had been trying to fix it for several weeks when I found it, and boy was I happy. I'm the one who needs to thank *you*!!! Thank you!!! :)

Thank you for the great page on DMA/PIO issues. I had a problem caused by Daemon tools that you covered on your page. Without your work I might never have solved this problem. I intend on donating again after my next paycheck.

You ROCK! Your write-up on Windows setting DMA back to PIO saved me. I was about to take a 12 gauge to my computer. My DVD player wouldn't work for SHIT (stuttering, dropping frames, etc.). I uninstalled my secondary IDE controller, re-booted, & problem solved. THANKS!

Your DMA reverts to PIO page relieved me from horrible sound stututustuttuttering. [...] Hard disk went from PIO mode back to Ultra DMA mode 5 when I uninstalled primary IDE channel in device manager and XP reinstalled it. Thanks.

I love you...
no i don't—but I'm really greatfull that you published this site [...] as I was quite desperate and 24 hours mentally down because my harddisk only managed 2,2 MB/sec (now, thanks to you: 66,2)
best wishes!

Wonderful Dude,
I just want you to know that your posts on how to fix choppy DVD players saved my butt tonight. I love the fact that I can go and search for an answer on the internet, and a good soul such as yourself will have taken the time to post such a clear and excellent series of solutions. [...]

I just wanted to thank you for the information [on this page]. After noticing that my laptop's CD/DVD drive started exhibiting the dreaded "choppy playback" from nowhere (probably caused by trying to read a poorly burned homework assignment handed out by one of my professors a dozen times) I found your advice after a quick search on how to correct the problem. After a few minutes of reading, using the provided script, and rebooting, my drive successfully reverted back to DMA mode from PIO.
Just wanted to give my thanks and have myself counted among the satisfied visitors who were able to fix the issue without any problems. I especially appreciated the down-to-earth explanations for and solution to the playback choppiness. CDs/DVDs play like a dream again, and that really makes my day.

I also wanted to thank you. I almost despaired. For no discernible reason all movies from my DVD drive became jerky. Cleaning the registry and scanning for viruses were also unsuccessful. I was already resigned to the thought of returning the laptop to the manufacturer, because I thought the drive was broken. Luckily there is the Internet and dedicated people like you, who help with good tips.
Many thanks for your work; the article is truly excellent. You're my savior, unthinkable now that I had almost reinstalled the computer.
I hope that many, who have the same problem, find your article.

Thank you very much for your online help to my DMA problem (DMA reverts to PIO). I had been banging my head against the wall for a few weeks before I found your site. The .vbs program worked perfectly to fix my infuriating iTunes & audio distortion problems. For this, I have donated $10 to your site.

Comments, discussion

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Typical symptom: PIO mode (see comment 761). JPG image30.33 KB

Re-enabling DMA

Fri, 2008-09-19 14:10 by john1951

Playing through my laptop's DVD/CD reader has been exhibiting exactly the symptoms that this help note addresses; that is stuttering on sound and vision on playing all dvds/cds, yet ripped and played from the hard drive or direct streaming worked fine. I have been homing in on the PIO/DMA issue described in the note for some time as it was the only analysis that seemed to make any sense, but the fix of uninstalling the secondary IDE channel didn't have any affect. However, I eventually spotted that device 1 on the primary IDE channel was stuck in PIO and ran the quick fix rather than the step by step approach. This solved the problem. Many thanks for the problem analysis and solution.

Thanks for reporting

Fri, 2008-09-19 19:32 by admin

Yes, the quick fix is very convenient and safe. It can also be repeated quickly, should the problem crop up again.

PIO to DMA - solution

Tue, 2008-09-02 17:18 by djuro bojic

People, I have tried a lot of stuff to fix it and the best solution was straight in front of my eyes!!!! Just uninstall drivers of the DVD/CD ROM device and reboot the computer. When it starts again it will install the drivers automatically and return to DMA mode by itself!!!!
I was so stupid, messing with Registry etc.

Yes, that works

Tue, 2008-09-02 17:44 by admin

As described in the article. But the easiest and quickest fix is still the little "Quick solution" program described at the top.

FINALLY fixed! Switch primary with secondary IDE cables!!

Fri, 2008-08-15 20:25 by ripples

Wow, after many hours I finally have a fix for my PIO-only Maxtor hard drive. I think this actually all started when I reformatted and installed Windows XP again. So I have been living with this chronically and just have gotten used to it.

Anyway, I tried everything--the vb code didn't allow me to boot up (expected since my HD was the only one), uninstalling the IDE drivers didn't work, updating drivers didn't do anything, trying to install the microsoft fixes didnt do anything, manually toggling from PIO to DMA if availble, etc etc etc.

The thing that finally worked was switching my hard drive from the primary IDE to the secondary IDE. (and my CDR and DVD which were on secondary now are on primary) After booting up this simple fix instantly corrected the problem and now I'm running at DMA 5. By the way, if people are looking for an easy way to check HD performance, there is a freeware program called "HD Tune" (search google) that works really well. It also can check for physical damage.

Anyway, thanks for the ideas here and hopefully if someone has a problem similar to mine they can try cable swapping and not go through that incredible hassle.

Check cables, etc.

Fri, 2008-08-15 22:16 by admin

Thanks for reporting back! Your solution, though perhaps working well, is not quite satisfactory, because it leaves the nagging question whether something may still be wrong with the primary IDE channel. It could be the cable or one of the plugs. It could be a wrong master-slave jumper position. It could be an improper sequence on the cable.

In theory the master device has to have the master-slave jumper plugged into the master position, and it has to be connected to the end connector of the data cable. A slave device, if present, has to have the master-slave jumper in the slave position and be connected to the middle connector on the cable.

But then I've seen all kinds of odd problems that were fixed by merely swapping something around. In fact I wouldn't be surprised if you put everything back to how it was before, and it would keep working just fine. (No guarantees though.) If you feel like it, you could try. If indeed it worked, I would suspect a poor contact that was fixed by the corrosion-cleaning friction of pulling and replugging the contacts.

But it could still be something else, and you could have found the best solution.

Thanks also for the HD Tune hint.

Another one saved...

Fri, 2008-08-15 18:08 by dugger

Another time your post saved a poor man looking for a solution!! In my case, everything started with a friend of mine telling me his windows xp has a crackling sound. I took a look at this pc, and found with Process Explorer that the Hardware Interrupts were taking a lot of CPU Kernel time, and everything was slowed down to pain. Reading a tons of web pages and forums, I found no solutions. I started haunting the device which driver would be the responsible of the interrupts cpu hard work, but with no luck. Fortunately I found your post, and checked immediately that the ATA primary device (the one with the OS disk on it!) was running in PIO mode!! A-ha! Found it!! And your quick solution, the vb script worked great way! Now everything is back ok!

Thank you very much. Your the right one!!

Thanks for reporting back

Fri, 2008-08-15 20:23 by admin

Thanks to everyone above and below for reporting the good things!

Yes, the VB script is a very quick solution. Should the problem reappear one day, you can quickly repeat the procedure.

thank you

Fri, 2008-08-01 02:49 by fuzzy monsters

thank you so much
this has been the bane of my existence for the past two weeks, the lag issues in photoshop CS3 have also been solved

thank you thank you

Big Thankyou!!!

Fri, 2008-07-18 17:20 by lxsed

Microsoft never ceases to amaze.... ;-(
Thank you for this clear and most helpful advice.

A week ago, experienced drastic system-wide slow-down, preceded by no out-of ordinary event.
Spent two days staright monitoring processes, scanning for viruses, spyware, defragmenting, cleaning-up, loosing sleep and tearing hair out in clumps - no results.
I have alredy decided to wipe the system and re-build from scratch, and would have done so, were I not to stumble across this article.
Primary IDE controller - Master disk with Boot partition(Win XP) - sure enough PIO!
Manually applied the registry changes.
Back to UDMA-5!

Whatever the primary cause of the switch to PIO may have been..... .....surface scan of the Master disk passed OK, so I can sleep well again.


Trap still open

Fri, 2008-07-18 18:59 by admin

Yes, the trap is still wide open and catching victims in numbers that are hard to imagine. Glad you got out.

DMA falling back to PIO

Fri, 2008-07-11 09:06 by joe909001

I did this using the manual method. It worked a treat. Thanks very much. I can now keep the rest of my hair. What bit i've got. Thanks again.

Glad to hear

Fri, 2008-07-11 10:27 by admin

I keep wondering how many computer users never find out and just live with a crippled computer.

Resetting checksum fixed me - symptom was stuttering audio

Fri, 2008-07-11 02:18 by FredMay

My symptom was stuttering choppy audio and video on my laptop playing files located on my hard drive. The problem just appeared, although there was an unusual BSOD that had happened in the recent history. Reinstalled audio drivers, media player, motherboard drivers, removed unused programs, uninstalled Norton Anti-virus, re-loaded codecs, and much much more - all to no avail. Spent days of work. I did not want to send the laptop to the repair depot - for them to reformat my drive and reload Windows, which would have solved the problem. Then - I finally noticed that the disk was using PIO and wondered why it was not DMA. I was not sure at all which was better. My first Google search found this page. I found the registry count Checksum was high and reset it to zero. Next reboot, the drive automatically chose DMA, not PIO. The audio and video stutter was completely fixed!. Thank you kindly. I am now considering that there may still be a looming problem with the hard drive, and might be well advised to image a replacement drive. Thanks again!

Thanks for reporting!

Fri, 2008-07-11 07:18 by admin

Nice success story. Thanks!

Just observe the drive's behavior over time. If it keeps falling back to PIO, then there's something wrong. It may well be the drive, but it could also be the data cable connectors or the controller on the motherboard.

But maybe it behaves from now on and all is well.

Spsp1981's picture

WARNING for DeepFreeze users

Mon, 2008-06-30 02:25 by Spsp1981

A little of history first, I came to this thread while looking for possible causes/solutions to a sound playback problem. Whenever I tried to listen to music / watch a video, the system slowed down. Using Process Explorer, I found out that it was because of "Interrupts" (Hardware interrupts) taking up the CPU. When I read this post, seemed a good possible cause, I checked my devices properties and one of my hard disk was in PIO mode. So that, I tried the registry fix explained, but after rebooting my 3 hard disks and the DVD drive were detected as new hardware. Suddenly, after the last drive was installed, my display turned off (Power saving mode) and the system stopped responding. As this has happened to me before due to a problem with the nVidia VGA driver, I rebooted in VGA mode but a BAD_POOLER_[something] BSOD (some other messages also appeared, many of them didn't even mention a cause) prevented me from trying anything. Luckly Safe mode did work and after a serie of try and error tests, I find out that DeepFreeze was the problem. Seems that DeepFreeze does not consider the hard disk to be the same after redetection. So, after several research and tries and errors, I was able to make my PC work again and here I explain how:

If you have DeepFreeze Standard installed, probably you entered in thawed mode to make the changes. The problem comes when you try to restart the PC, new IDE channels and HDs are detected but the PC no longer works showing some BSODs and/or the display turns off a few seconds after loading the desktop (Exactly when the DF's tray icon should appear). There are only 2 options I can advice, first one is the obvious one: uninstall DF prior to making this fixes. Second one is when IT'S TOO LATE: here's an article that explains how to manually remove DF without reformating your computer:

"NOTE: I'm not responsible and/or affiliated to the above mentioned site and tutorial. I just luckily found it."


Mon, 2008-06-30 09:26 by admin

Thanks for this important information!

Installing questionable software, particularly software that intrudes deeply into the operating system, can cause serious, sometimes intractable problems.


Thu, 2008-06-26 14:23 by macHelp

If only all info was even half as good !


Thank You, Thank You, Thank You ! ! !

Thu, 2008-05-22 09:34 by greenylad

Have spent days trying to find out why my system was slow and any media playback was very stuttering and poor. used this to find that my primary IDE was in PIO, ran the simple script and hey presto, all is fine and it's back in DMA 5 ultra.
What a fatastic site.
Book marked for future and a small donation on it's way :-) :-)


You are the Mannn!

Sun, 2008-05-11 16:24 by amircoh28

Thank you so much. you helped me a lot.

You are awesome

Tue, 2008-04-22 02:05 by immortalsuby

I love you.
I spent hours upon hours, combined with months of a slow hard drive, trying to isolate and fix this problem. Your page told me exactly how to solve it and it worked great. DMA 5 again!

forgot to add...

Donation sent. Thanks again! :D

thank you so so much!!! i am

Sun, 2008-04-20 07:11 by soadserj

thank you so so much!!! i am so happy i can finally watch DVDs again!!! i sent you a little donation. i wish i could afford more, but you guys still are the best!

DMA is back!!!

Thu, 2008-04-10 03:04 by dc9driver

Nice little script!!! Did the trick perfectly. A little donation coming your way :)


Thank you all!

Thu, 2008-04-10 16:00 by admin

A little donation is, of course, always very welcome.

For those with the ALi M5229 IDE Controller

Sun, 2008-03-30 16:36 by Arran

Occasionally a chip set or controller driver is buggy, so check with the manufacturer for updates.

2007-03-01 – Francois Eraud reports one such case in a Sony laptop, regarding an ALI M5229 chip set controller, solved with driver version 4.008.

I spent ages suffering with choppy sound playback within windows and it seemed to be due to hard drive activity.. I wasn't wrong, I tried an older smaller hard drive and it jumped straight in to dma mode.. My new 160gb drive was stuck in pio (pio has high cpu usage which was resulting in my chopping sounds)... So I did a search and found this site... Helped me out loads...

Anyway mine was due to the chipset as said above in the quotation... I managed to hunt down these VERY rare drivers....

If you're concerned about downloading a random file from some randomer then here is all the details...

I believe this will sort the problem for those with the ALi M5229 IDE Controller... Doesnt matter what brand of computer you have.


Windows Vista or 7 compatibility

Tue, 2011-01-11 00:02 by Overfloating

This fix works great for Windows XP. Has anyone got it to work for Windows Vista or Windows 7? I have tried several different methods in my attempts including:

Installing the driver in Windows XP then trying to install Windows 7 over it. Installation fails before it gets started saying the driver is incompatible.

Installing a clean version of Windows 7 which takes excruciatingly long in pio 4 mode. At least 4 hours. Then trying to install the driver. After a driver warning pops up (I click "Continue") the computer reboots and goes straight into trying to repair the windows installation, which it fails to do. Only option is to then reinstall.

Installing a clean version of Windows 7, and manually installing (in Device Manager) the drivers for each IDE Channel and controller. The application of course never gets installed this way. This method fails as well.

I've also tried to break the drive into partitions under the 137GB limit (though I know this is more of an OS support problem it was worth a shot) around 100GB each with the same result. PIO mode 4 in all cases for this attempt.

So since we know that this driver sets up (emulates?) a SCSI interface does Windows 7 not like SCSI drivers? Anyone get it to work with Vista? I would like to use a somewhat more modern OS if possible and I like Windows 7. The computer runs Win7 just fine on a 40GB hard drive. It's intolerable under 7 with my 320 GB drive. My hope is the driver would fix this issue.

My gut says it's Windows 7 and the SCSI emulation incompatibility but I defer to someone who may know more. I should also mention my Windows 7 (and XP) version is 32bit.

Thanks for any input!

Hibernate and stand by no longer available.

Wed, 2010-01-06 19:01 by mrfixit

The IDE4008.exe file fixed the problem for me on my Vaio PCG-K23 laptop. I too have the ALi 5229 chipset and a Samsung 160GB hard drive. But now there's a new glitch. Hibernate and stand by mode are no longer available. Any fix for this?

Thanks for your reply.

Hibernate and Standby Fix in XP after IDE4008.exe Update

Sun, 2011-01-02 22:39 by warmech3

If Hibernate and Standby No Longer available in XP after installing IDE4008.exe, You can fix this by making one change in your registry.

Be Careful ! Back up your registry if you can.

1. Click on "Start" Button (leave out all " " they're just to enphesize what to do)
2. Click on "RUN"
3. Type in the box "regedit.exe"
4. select HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/alihdd/Parameters/PnpInterface
5. Highlight "5" in the righthand side, right click the 5 then select "Rename", Replace "5" with "1".
6. Reboot

good luck
p.s. if you can't find the IDE4008.exe it's available at

New Driver solved problem with ALI M5229 chip / Large disk

Sat, 2009-06-06 07:41 by chetto

Thank you so much! I noticed a few weeks after installing a new WDC 250GB drive in a an old (circa 2003) HP laptop that came with a 30GB drive, that the disk was slow because it was in PIO mode. I did all the steps I found on the web including MS KB817472 to adjust the Registry keys, reinstall the IDE driver, etc, but nothing made a difference.
I suspected the fixes didn't solve the problem because of the BIOS (XP and Linux live CDs see the entire 250GB, but the BIOS only reports 137Gb). Since no BIOS update exists from HP (for ATA 48bit LBA), I was about to give up when I found this forum thread mentioning the new ALi IDE driver. My laptop has the ALi M5229 IDE controller so I installed the new ALi driver referenced here and it worked! According to HDtune benchmark, before the update the entire disk was a constant 2.1MB/s. After the driver update HDtune reports a steady 45MB/s for the 1st 128GB and a steady 2.1GB above 128GB. The disk is partitioned into 5 partitions with a partition boundary at 128GB. There is a also a major drop in the CPU usage for disk I/O. The performance difference is dramatic since XP is installed on the 1st partition.

The only downside is that the new driver leaves the original ALi IDE controler in the Device Mgr (w/o any channels) and adds a pseudo SCSI controller with the IDE primary and secondary channels, but no longer has the Advanced tab displaying the configuration. The driver does install a separate program that displays the transfer mode of the IDE channels.

worked like a charm

Sat, 2009-01-03 05:06 by goldflowerinc

The IDE4008.exe driver installation program mentioned above worked for me, as I have an ALi M5229 IDE controller on my HP laptop. It can't hurt to try the vbs file mentioned at the beginning, as I did this as well. But since I had done the registry editing manually to no avail prior to finding this driver, I think that the new driver is what fixed it. So many reboots! Even once I installed this driver, I had to reboot twice (once per channel) for the driver to finish "installing new hardware" but already after the first reboot I noticed (and heard) the speedup (no stuttering Windows intro sound). Now my hard drive is no longer the bottleneck. I have a HP Pavilion ze5600 with the ALi M5229 IDE Controller and a Hitachi hard drive. Thanks so much to all who posted!!! - Charles

ALI M5229 responsible for DMA failing to PIO for Samsung drive

Sun, 2008-05-11 15:10 by GigiDuru

I newly bought a Samsung 160GB drive on an old system as a secondary drive. It failed from the very beginning to PIO, with the following errors shown in system log (event viewer):

Event Type: Error
Event Source: atapi
Event Category: None
Event ID: 9
Date: 5/11/2008
Time: 5:02:49 PM
User: N/A
Computer: SUNSHINE
The device, \Device\Ide\IdePort2, did not respond within the timeout period.

And yes, Arran, you were right.
I first tried the registry modifications, but it did not work. Of course, all the HW testing was tried as well (moving/changing between IDE cables, and so on...).

This ( did the trick. It is a rare drive, indeed :)

THanks a lot!



ALi/ULi unified driver 2.20 (ALiIDE version 1.51) also works

Tue, 2008-12-02 22:18 by avbohemen

Thanks to this site I found the solution to a 4 year old problem on my brother's laptop. It also has an ALi M5229 controller and it was running in PIO mode on a Seagate ST94011A harddisk.

I decided to go with the latest ALi driver I could find. It's now on the NVidia site, after they had taken over ALi/ULi, here: The SCSI emulating driver has been a workaround since UDMA became popular and Microsoft and other vendors had no well-working IDE/ATAPI drivers. That got solved slowly but surely after a while, so now I just wanted to use the ATAPI driver. I can imagine though, that the IDE driver above is a last resort for devices that absolutely won't work in UDMA mode.

After the driver update I used the resetdma.vbs script, and it worked fabulously! The disk is now on UDMA mode 5, instead of PIO. Strangly enough, the DVD burner in the laptop has always been working at UDMA mode 2...

Thanks a lot for these finds

Sun, 2008-03-30 18:25 by admin

This is very useful information for users with this controller chip.

WilhelmR's picture


Mon, 2008-03-24 19:28 by WilhelmR


DMA Reset

Fri, 2008-03-14 00:09 by efabrizio

Thank You, Thank You, Thank You. Worked like a charm !

Thanks for reporting back!

Fri, 2008-03-14 10:45 by admin

Glad it worked.


Sun, 2008-03-09 09:04 by Gremlin

It's been so long since I'd even looked at HDD modes that it never occured to me to check if it was in PIO mode or not, I checked and hey presto, there it was, in PIO mode. After reading your post fully, I used one of your suggestions, (removal of offending drive in the Registry) rebooted, and now it's now no longer in PIO mode, its DMA Mode 6.

Thank you, as in the previous posters case, you saved me buying a new HDD.


You're welcome

Sun, 2008-03-09 10:11 by admin

If you like, you can donate a small fraction of the money earmarked for the new drive here (see "Donations" at the top). smile

Thank you

Sun, 2008-02-24 22:58 by chernobyl

Hi, I just wanted to say thanks. This article actually saved me from buying a new hard disk!

Nice to hear this

Sun, 2008-02-24 23:22 by admin

Thanks for reporting back!

DMA reverts to PIO

Mon, 2008-02-11 17:20 by tippy

I had this problem and it turned out to be a failing DVD burner, which gave up the ghost this morning...In it's final death throes, it came up with CRC errors.Good idea to swap out any drive on a channel that starts acting flaky.Hope this helps someone.

Hardware error

Mon, 2008-02-11 18:48 by admin

Thanks! This is a good reminder that recurring errors and recurring fallback to PIO can indicate a hardware error.

DVD drives fail fairly often, hard disks also fail sometimes. Cables can break, contacts can work themselves loose, and even controller chips occasionally fail.

All of these failures can lead to PIO fallback.

Thank you, It solved a problem ...

Fri, 2008-02-01 10:48 by dmpriso

with a Dell Inspiron Notebook and Windows XP. It was extremely slow and stuttering, and according to Process Explorer, "Hardware Interrupts" were consuming lots of CPU time especially when accessing the harddisk.

Your script helped.

But it's interesting - the notebook does have a built-in intel SATA controller for the HD, but resetting the PIO mode for the Primary IDE Channel helped, or does your script reset the PIO mode for all devices?

Script resets all channels

Fri, 2008-02-01 12:04 by admin

Glad it worked for you.

Yes, the script resets all channels. Since this is a harmless operation, it is easiest and best to reset all of them.

You can download the script and look at it. It is a relatively simple Visual Basic Script program that goes through the registry and removes certain settings.

Thanks again, it helped a

Fri, 2008-02-01 12:59 by dmpriso

Thanks again, it helped a lot and solved a problem I wasn't able to track down exactly for weeks.

Marieaa65's picture


Tue, 2008-01-29 03:01 by Marieaa65

Thank you Thank you, I hit < Here> and it fix my stuttering on my D L Dvdplayer, I have tryed to get the company I bought it from they could not figure it out, Works so great now, sound is perfect.


Tue, 2008-01-29 07:33 by admin

This problem is apparently hitting millions of people. Glad you could solve it.

Still PIO

Fri, 2008-01-18 07:48 by bert02

ok i have read everything on this page and my pioneer dvd burner 112 is still in pio
bios is enabled
i uninstall ide ata/atapi channel and it loads as pio still
tried all registry fixes, and that app still doesnt work
was working fine b4 so it has the correct cable
any other help?

May still be a hardware error

Fri, 2008-01-18 09:16 by admin

Cable contacts can corrode, work themselves loose or even break. Try taking the cable out and reconnecting it to reseat the connectors. Reseat the power connector as well.

A bit more likely is that the drive itself broke. DVD burners often break too.

My bet is, if you connect a new drive with a new cable and then apply the fix, it will work.

Can you try that for a test? Borrow another drive with cable or take the computer to a shop and let them test it?

One can never be entirely sure, because it could still be the motherboard that broke (a chip turning sour, for example), or it could be an uncommon software problem, but I think those causes are less likely.

Wow, you made my day! Thanks!

Fri, 2008-01-04 13:49 by wyldstallyns

I reinstalled my secondary IDE channel as you instructed, and you solved my problem!! I just purchased $300.00 monitor speakers for Christmas. I was so excited to accustom my ears to them with various CDs, but lo and behold - my DVD-R drive was chopping the audio to shreds.

I've been trying to find a solution for days, and your's worked! Thank you, thank you, thank you.

In fact, I created a profile here JUST so I could thank you!

Take care.

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