Lars-Erik Østerud said:
Suddenly my Plextor 716A got terrible problems and slow writing.
After some checking a saw that the max DMA mode (in Hardware control
panel) is PIO and not DMA, even if "DMA if available" is set ON.
And I cannot change it. DMA is on in BIOS and max DMA is detected
right in BIOS. What can cause this? How do I fix this in WinXP?
Hi Lars-Erik
Windows can switch to PIO mode on a drive after a certain number of
time-out or CRC errors. Here's a quick method that should fix it for
you, originally from MVP Alexander Grigoriev.
Run Regedit and got to to the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E96A-E325-11CE-BFC1-08002BE10318}
It has subkeys like 0000, 0001, 0002, etc. Normally 0001 is the primary
IDE channel, 0002 the secondary, but this isn't always the case (on my
system for some reason 0002 is the primary channel). You need to go
through these subkeys and check the DriverDesc value until you find the
correct IDE channel.
As always, it's a good idea to export the key data as a .reg file before
changing the registry, just in case you should need to restore it. Then:
Delete MasterIdDataChecksum or SlaveIdDataChecksum, depending on whether
the problem drive is attached as master or slave, but it can't actually
hurt to delete both. Reboot. The drive DMA capabilities will be
redetected.
Open Device Manager again and check whether the device is now actually
using DMA mode.
Hope this helps
Let us know how it goes!