CPU OC big boost in gaming experience?

Solution
If either:

1/ Your game is heavily CPU-intensive and doesn't need much graphic power ( some MMORPG games, like TERA for example ).
2/ Your CPU is bottle-necking the GPU ( full load on 1/2/3/4 cores of the CPU ( depends on how many CPU cores that game you play can ultilize ) but only 80% or less GPU usage while gaming ).

Then yes, OCing the CPU will help improving the FPS.
Like keith12 said, we need your specs to know. It may or may not. If you have a sandy/ivy bridge i5 then ocing will likely do little to nothing. For example, I just got a second 7870 and was playing tomb raider last night. My 3570k cpu usage never went over 40%. An OC would be pointless for that game.
 
If either:

1/ Your game is heavily CPU-intensive and doesn't need much graphic power ( some MMORPG games, like TERA for example ).
2/ Your CPU is bottle-necking the GPU ( full load on 1/2/3/4 cores of the CPU ( depends on how many CPU cores that game you play can ultilize ) but only 80% or less GPU usage while gaming ).

Then yes, OCing the CPU will help improving the FPS.
 
Solution