Here's our test system.

Windows Vista 64-bit SP1 was our OS with Catalyst version 9.5 for testing. V-sync was disabled.

We'll start off with Crysis which primarily uses two cores. Here we see the Phenom II X2 550 do quite well scoring fps and topping the Q9300 from Intel. The 7850 which runs at 2.8GHz lags 12 fps behind. The Athlon II also lags a bit due to the lack of L3 cache at 50.7fps despite being only 100MHz slower.

Unreal Tournament 3 supports multiple cores so the Phenom II X2 can't top the Phenom II X3 which almost matches the X4 955. That said the Phenom II and Athlon II are still much faster than the 7850.