Well, it would REALLY help if you listed your system specifications.
*And what games you have these problems with.
AMD FX 8350
Radeon HD 7850 1gb
650w Antec PSU
Games I have a problem Guild Wars 2, The Witcher 2, DOTA 2 (All on Max settings) (DOTA is the only game where I get a stable 60 FPS)
Games I can play that I haven't noticed (Max Settings) Planetside 2, Hawken (Even thought I only get like 20 to 30fps)