dang! i love those 3800's! in game speeds are a little slow, but...

Left: CMR DiRT at ultra settings in 1280*1024 with 4xAA and 8xAF Magneti Marelli Crossover (droven complete) on my HD 3870 without any modification. That's at least 40% faster than an 8800 GTX, 25% faster than an 8800 Ultra, in simple worlds: faster than any Nvidia-card on earth.
Right: Crysis in 1280*1024, all settings high, 4xAA, 8xAF, AAA on, VSynv on. 30 fps limited by my P4 with GPU load at 80%.
I'd think gaming performance does match OpenGL performance as shown with this benches.