Download the free version of LatencyMon and run it; there's a good chance it might reveal the problem if it's hardware related.
http://www.resplendence.com/downloads You might also pull up the Task Manager and see how many processes are running in the background. My quadcore has 35 processes running in the background, with no other software booted.
If there are a lot of processes running, make sure the start menu is turned off.
Based on recent posts, disabling the wireless adapter and bluetooth port using the device manager might help.