Overclocking & game performance

Hi all, i'm not sure i'm posting this in the relevant section, so mods please amend this if it is in the wrong section. Thanks.

Does increasing (overclocking?) the speed of the cpu of the 2nd gen 1ghz phones (htc desire hd for example, with the adreno 205 gpu) increase the FPS and or improve general performance when playing graphic heavy games (like dungeon defenders, reckless racing, and modern combat sandstorm) on the device? or would the gpu have to be improved separately in some way to gain any benefits when playing games?

Thanks

Ian