This is a problem I've dealt with a few times....I had a problem with having a cdrw and a dvd drive on the same ide channel, 1 can be dma and 1 has to be pio. I had a problem with the DVD not playing right if it wasn't master w/ dma enabled and cdrw had to have DMA or it was real slow and cpu usage was high. This is what I've found.....I could be wrong...but I'm pretty sure that is right. On my old system I fixed the problem by putting the HDD on the raid controller (w/o setting up raid) and each optical on a different channel.....all were in DMA mode and all were happy...seems silly but it worked...