Is it the ITE IT8212 ATA RAID Controller ? I would suspect that raid card - the few I've tried didn't work well even with the manufacturer's supplied windows drivers. The linux drivers might not be any better. I'm not sure why you distrust DMA, or if it's just on this one card that you have problems with it. ATA is being phased out now, it became a very mature and reliable technology its it final years. Motherboards with onboard ATA66/100/133 ports became extremely reliable. As long as you used the 80 wire cables. Unfortunately, a good controller is hard to find. I used to like Promise as a windows controller. They were very reliable if you had the lastest firmware and drivers. But I don't know if they work well in linux, or even how well their current models work. (been a while since I've used one)