Our low quality gaming tests don't show a very realistic scenario considering games are more GPU reliant, but still give us some indication on how CPUs stack against each other.
Percentage-wise our Phenom II overclock was good for a 9% rise in performance in Unreal Tournament 3.
The Phenom II is not too impressive in Crysis Warhead. The Cry Engine seems to like Intel processors better in general, though it's ultimately the graphics card you run that will mandate performance when turning up resolutions.
The Phenom II X4 fared much better in Far Cry 2 overcoming the Core 2 Duo E8600 and the Core 2 Quad Q9650 processor after the overclock boosted frame rates by 5%.