Promise fasttrack sx4000 hickup on video file playback

[supafraud]

I just got a fasttrack sx4000, im booting off of it with 2 WD 160 gb with RAID 0. I have a stick of 128mb of ram in it right now. Because i am booting off of it and am using XP i had to use the 64k block size. When I play DV files off of it, they play jittery and choppy. This confuses me, because i used to have a fasttrack66 and there was never a problem. I have the latest BIOS and drivers for it, is there something more I should be doing? Hardware conflict? Does swapping PCI slots really make any difference? I have it in the last slot because the damn card is so big. I guess I could move it, but not if there are other things i can try first. The wierd thing is also, when I run hdtach, it read at about 39MB per sec, and DV files are only 3MB per sec. Whats the deal? HELP!