Some more info is needed please:
"clean install twice without fully formatting the HDD" err.. how did you manage that?
"i run like 5 different programs to check" What are they and are any running in 'Real Time'?
"RAM is fine" How much RAM do you have installed?
What O/S have you got? (W7, Vista, XP?)
Have you looked in 'Task Manager' to see which programs are using the CPU?
What is the Make and Model of your pc? and is it partitioned?