DMA reverts back to PIO

I know this is a repeatedly asked question and but everytime i turn my computer off, the DMA mode always reverts back to PIO. I can get back to the DMA mode by removing the IDE controllers and rebooting. I’ve actually found that reflashing my FW does a quicker job of resetting the DMA.

I read one thread that had a link that gave some great suggestions on changing the windows registry but I’m too chicken to try this in fear of screwing up the registry. Can someone convince me that I won’t screw up my registry if I try this fix?

Are there any other suggestions? Is it safe to reflash the FW everytime I want to read/write/burn?

Here’s my system:
Dell 4500, XP, SP2
Plextor 716A, FW 1.08, 80 pin cable

I just regestered on the forum, but have been learning a lot for the past few months. Thanks to all that make this forum possible! :wink:

Is your drive on its own cable? Reversion to PIO indicates a problem reading and Windows reversion to a slower mode. You may have to do the reg. hack if it has happened repeatedly. Be careful, the link you posted seem fairly complete. Save a backup copy of the registry before you start and then you will have something to fallback on.

I’d check the cabling and/or other devices on the same channel. As Chas pointed out, DMA->PIO fallback in Windows is due to one of two things:

  1. The DMA negotiation failed somehow.
  2. Too many IO errors on that channel.

Bad cabling, or devices that don’t get along, is the number one cause of this sort of fallback.

Thanks guys. You definitely pointed me in the right direction. As it turns out, it was a hardware problem and not a software problem as I thought. It was a jumper conflict between my Plextor and CD-Rom drive. When I installed the Plextor, I put its jumper on master and I forgot to switch the CD-Rom’s jumper (which was set to cable select). Putting both jumpers on cable select did the trick. Thanks again for your help!

Wish they were all that easy…

I’ve had exactly the same problem on my Windows XP system.

Another thing I’ve noticed is that my Hard Drives on IDE channel 1 are on DMA Mode 3 but my DVD and CD drives on the second IDE channel are on DMA Mode 1. Is this correct?

I used to uninstall the IDE channel to fix the reverting back to PIO mode problem, could this have caused problems with the DMA Mode?

I have always used the Master Slave configuration so how does Cable Select work?


What drives do you have connected. I read somewhere that nothing made was officially DMA 3 so your connection is weird or my information was bad. I assume 80 wire cables.

Cable select can be a problem and is just a short cut to Master/Slave. Avoid.

Read here as well:

It an old Pentium 3 700mhz system. I think the cables are 40 wire - how can I tell? Motherboard is a Tyan Trinity 400 (Ultra DMA 66).

Hard Drives are a Fujitsu MPE3204AT and Seagate ST320420A both at DMA 3

I had a Plextor 504A and ASUS CRW-5224A both at DMA 1.

I just tried a Plextor 712A on its own as master and this to is at DMA 1.

Also uninstalled all IDE channels and controllers but still getting the same config when rebooting.

Hi, I’ve a question about DMA/PIO on my hard disks…

I’m upgrading from a 20Gb drive to 200Gb. I’ve plugged the 200Gb in as the 2nd device and now have a dual boot (both Win2k).

This is fine but I notice when on the original system, the mode for the 200 disk is PIO. On the new system they are both Ultra DMA.

(Maybe this is why my music clicks and blips on the first system ?)

Should I switch the drives around (i.e. make the new 200G device 0), and is this risky business ?

Appreciate your thoughts…

Sounds like it can def be BIOS related… is BIOS fully up to date?

Looked at BIOS, both drives set to Auto…

Since both systems in dual-boot are Win2k (both latest versions), I presume it’s software.

Haven’t a clue where to start looking tho…

sorry for bumping here… but
i have a p6n sli msi mobo and 2x 80gb WD, raid 0 sata (both are the exact same model) and everything is working neat and fast

then i setup another systemm p6n sli platinum with 2x 250gb hdd sata on raid 0 and they are stuck on pio mode. now… i do see that they are not the exact same model… both are WD but not the same exact model.

Maybe you can update the BIOS, especially the controller bios and the drivers for sata.

well… done that… been there…
but i actually found a fix xD
see… when i installed the OS i used the disk that came with the MB to install the drivers…
then used the drivers on the MSI website…
wanna know what fix it? the nvidia driver from the nvidia website… lol…