it’s amazing…the way one moment of random PC sys…

it’s amazing…the way one moment of random PC system settings’ seeking can lead to an utterly enlightening experience of System tweaking (here and there) (did I just write that?)

anyway….it was when i began copying some files from a local-fixed HD to a USB 2.0 -External one when i realised that the copy process was pain-stakingly slooooooow…..Root of problem: DMA transfer mode.

Technical background: DMA (Direct Memory Access) transfer modes: PIO (programmed input-output) for old HD drives and Ultra ATA (UDMA) that start for Mode 2 (44 MBps) and result in Mode 6 (166 MBps) for newer driver. End of technical background.

The reason for the slow copy procedure was that the local-fixed drive controller (Secondary cable – IDE) had dropped it’s transfer mode to PIO from UDMA. This happens when Windows detects I/O timeouts (i think >6 timeouts drop the mode).

Solution that worked for me:

- reboot -> enter bios -> load optimized defaults.

Other solutions that may work for you:

- deactivate the Secondary Channel -> reboot -> let Windows reenstate it (and see what happens next).
- if BIOS doesn’t seem to support UDMA for the drive flash-upgrade it following the Motherboarb manual instructions carefully!
- if BIOS supports UDMA for the HD drive make sure that the motherboard driver is the one running in Windows environment instead of Windows native atapi.sys.

You will inevitably have to dig your way into Registry caveats but beware…

And another thing…if you run into video playback problems check DMA settings. Just thought it would help to mention it…

More useful info here:
http://winhlp.com/WxDMA.htm
http://www.pcbuyerbeware.co.uk/IDE.htm