Odd lagging and sound issues in game

Recently I got a new graphics card and have been experiencing some weird issues. I start up a game then it runs fine for a while then suddenly the sound starts to get distorted and i get a lag but my fps is still like 60. I close out and look at the task manager and the cpu usage is extremely high. I restart the computer then its fine. Other times I can have a whole gaming session without any issues.

Here's my specs:
gateway DX4822
Pentium(r) dual core e5300 2.60GHz
6 gb of idk what type of ram
gtx 550 ti 2gb

also i recently put in a new power supply, since my last one went out, it's like a 530w and to get to it had to take off the cpu fan then re-glued it after.