One thing i have since learned after my trouble with the winxp hack is that some motherboards operate the SATA ports as though they are part of the PCI bus, instead of routing them through the south bridge chip as normal ATA drives are. this means that if you have other things going on in the realm of PCI, that is like graphic, audio, or whatever, then it will slow down significantly while it is doing anything with the SATA drive. I assume that because it is a RAID setup with normal ATA, the slowness of the SATA would slow down the ATA... that's just a guess though.
on another note, emailed the guy that wrote that raid 5 tweak article and haven't heard back from him. and still have no luck trying to run the raid 5, though i've heard that raid is probably not good for my setup anyway, since i do a lot of audio, it would only be good for like a mirror setup for backing all my work up at the end of the week or whatever.