Mass Effect 2
In Mass Effect 2, you immediately notice the improvements made to the Unreal engine. While Alpha Protocol and BioShock 2 are content with a dual-core CPU, Mass Effect 2 needs at least four cores. Looking at the frame rate increase and hardware utilization tells us that this game would happily make use of an even faster CPU. Overclocking the processor yields somewhat diminished returns, though, with utilization dropping slightly. The game actually seems to treat our 3 GHz quad-core configuration as something of a sweet spot.
With this game, you should grab a quad-core chip and then start looking at graphics card upgrades. But don't lose any sleep over this issue. All hardware combinations tested produce smooth frame rates. We couldn't set the anti-aliasing to 8xAA via the in-game settings, so with AA deactivated, the game uses just 454 MB of graphics memory.