Computer Running Slow Randomly?

[DDoSd]

I spent about 1,100$ making my own computer. I got excellent parts, I'm confident I didn't buy a lemon.

About a month ago, it was running BF3 on ultra no problem. Now I can't run LoL on high detail.

My connection seems to be a bit higher then usual, but that could be the LoL servers.

How do I check whats the source of this problem?

 

[Wy479]

Check task manager for details whilst playing the game. Use that to find the problem

 

[DDoSd]

nothing.

 

[Wy479]

Nothing out of the ordinary? No applications that youve never seen b4?

 

[simon12]

Check your temps and CPU & GPU usage.