Hi
I have a 3.4GHz, 1G RAM pc with nvidia graphics. The motherboard is the
gigabyte GA-81915G-MF which has on-board sound. I have 2 optical
drives: liteon DVD R/RW and old HP cd R/RW.
I have the latest directx, and latest graphics driver for my card
installed.

When I play DVD's, the playback is stuttery (both sound and video).
When I play an audio CD on the DVD drive through windows media player
using their digital playback option, the audio is choppy. However if I
play the same disc on my older CD drive, also using the digital
playback option, the audio seems fine.

I have both optical drives connected on one IDE ribbon, to one IDE
port. My primary IDE channel Device 0 is using Ultra DMA mode 5, Device
1 is set as use DMA if available, however the current transfer mode
states "Not Applicable".

The secondary IDE channel: Device 0 is set to use DMA if available,
however current transfer mode states PIO mode.
Device 1 is set to use DMA if available, and current transfer mode
states "Mlti word DMA Mode 2".

My hard drive is a serial ATA drive, second hard drive is a USB drive.

I am a bit confused about serial ATA - is this the primary IDE
controller, and does this explain why under the primary ide channel,
only device 0 gives a current transfer mode? If this is the case, then
my two optical drives are on the secondary IDE channel. How do I
determine which optical drive is which (device 0 or 1)?
Finally, in searching for answers to the choppy playback problem, most
solutions involve getting DMA set correctly on the DVD drive. How do I
ensure that DMA is used on my optical drives - and will this fix the
problem?

thanks
Allen

OK, apologies, this seems like a fairly common problem. Windows XP had
"turned off" DMA for my DVD drive, and you can't enable it again
without a bit of fiddling.
I solved it using the registry-hack solution available at:
http://www.michna.com/kb/WxDMA.htm
This also explains why the CD drive played correctly since it still had
DMA.
cheers
allen