I'll run some tests on the GTX 480 tonite Jon. CPU @ 4500/4000 speeds and card around 900ish with bios 0007 and 0015.
With the GTX 295 I tried Gen2 and Extreme Tweak ON/OFF, the Nature was each time 300-400 FPS slower than 0007 (not steady 999 as with 0007 during the Nature benchmark)
Keep you posted