I actually did, orginally, have my 2 drives in raid0, but I wasn't really noticing much difference in performance (I think it's because they are pretty fast drives already - [WD raptor 10ks]), so I changed it back for easier reinstalls (no driver disk needed, and I can leave stuff on drive D as I reinstall a lot.

This is my second time trying raid0 on commodity m/b and not being impressed. I really think you need a dedicated, hardware raid controller to notice the difference if you've got pretty fast drives in the first place. Or at least that's been my experience.

Also, I tried splitting the wow dirs across drives and that actually slowed it down. My theory is that when it's all on one drive, and since it's a link, the disk caching can work for you when loading the Nth version of a given file. I noticed a significant loading/zoning performance boost when moving to one linked directory as I describe in the above link.