PC feels like its not running at full potential?

Specs:
cpu: amd fx 8350
gpu: msi gtx 760
Ram: 4gb
It just seems like its not running at the best it can. Like, in gmod ill sometimes drop in the 15~ fps area when i move around welded parts. Is this just the game? I just built it to. Maybe i'm just being paranoid. Minecraft doesn't go a drop below 60 so

Added (1). 1: i said i just built it
2: i use ccleaner every 2 seconds

Might want to delete some spam