Actually, I just made an embarrasing discovery. I didn't check the auto-detect on my RAM, and when I did my cpu-z validation just now for the owner's list, I noticed it was running at a default of 666 instead of the 2133 it really is (yuk). I fixed that and I'm getting better results. I'll post them to the thread where Vega's been posting his and where I posted my flawed ones earlier today.
Hm, the plot thickens. Now I'm back to the previous transfer rates. What changed since I started windows? When I got to the desktop, I was getting over 3GB sequential reads, now I'm down in the 2.6 range again.