Best System Diagnostic Tools

[urb1972]

Hmm, didn't know which was the best topic to post this in.

What are the best types of system diagnostic tools you can use (freely)? My system is running laggy and I wondered if there was any software that can test it.

Cheers

 

[pelvis_3]

This link will surely tell you what you need, you may even get more than what you wanted!