Since game benchmarks are all fairly straight-forward, I won't go into drawn-out discussions about every graph, unless there is something specific that catches my eye.
Call of Duty

Here we can see that the X2 improves on the 2.2 GHz Venice's performance by 6 FPS, though ultimately falling behind the Venice @ 2.89 GHz, Pentium 4 560, and Venice @ 2.4 GHz anyway. I would say that a relatively low-utilization thread has probably been off-loaded to the second core, such as sound, allowing the other core to focus primarily on graphics, and gaining that 6 FPS.
Comanche 4

Here the X2 is tied with the Venice @ 2.2 GHz, with the other two AMD chips dominating the chart. Intel's Pentium 4 560 is beaten even by the 2.2 GHz Athlon 64s.
Doom3

Doom 3 shows us much of the same thing. The Athlon 64s dominate the chart in the order of their clock speeds, and the Pentium 4 takes last place.