The Tegra2's gpu is about two times faster* than the SGX535, which means the OMAP44's is actually better because the SGX540 is better than Nvidia's GeForce-ULP.

Here the Atrix vs Droid3:Viddler
The Atrix gets roughly 54fps, whereas the Droid3 is bottlenecked at 59fps for the screen refresh rate on Neocore.

On Quadrant, both the Atrix and Droid3 gets ~2500. But I know Nvidia rushed Tegra2 to market, and I know TI is a quality brand, so I think the I/O rates would be higher (most probably) on the OMAP SoCks which would give them another advantage.

So the T20 needs to be slightly overclocked to match the 4430, or pushed much harder to match the 4440, which we know usually costs battery life :\

THIS is a good read