P4C800E-Deluxe + Opticals = PIO Mode

[isochar]

I'm trying to figure out why my Plextor Premium and NEC 2500 are running in PIO mode. They had been in DMA last time I checked. They are both on the secondary channel, with the Premium as the master. The primary channel has my two WD hard drives running in DMA, so it doesn't seem to be a chipset issue. The "DMA if available" is selected, so there must be some other reason for this. :/ Ideas?

[Wombat]

Try them one at a time. One device can bring the other down.

[ayoub_ibrahim]

If you are not using any of the onboard SATA interfaces and then try switching from enhanced mode to compatible board in bios.

[isochar]

Tried them one at a time and both result ran under PIO mode. Also tried the compatible default in the BIOS and that didn't work either.

[ayoub_ibrahim]

tried uninstalling the ide channel that they're on in device manager then rebooting?

[isochar]

Actually, I swapped the device cables and they are all recognized as DMA now. The opticals are on the primary channel and the hds are on the secondary. Weird. (Especially since it worked fine before.) *edit* This brings up another question that I've been curious about. The "old" opticals and the storage drives are occupying the drive letters still. How do I go about releasing them? Do I have to power down again, swap the cables back, uninstall all the drives, power down, and then reboot with the cables the way I want?

[The PIT]

Administrator tools > Computer management > disk management. You should be able to assign drive letters there.