Is it always "stuttering" or just once in a while?
Start -> Run -> "C:\Program Files\Java\jre6\bin\jqs.exe" -unregister
Might help a little
I'm looking at my windows task manager right now and System Idle Process goes from 100% CPU Usage which I know is normal and drops down to like 22% when the freezing happens
At the processes, click on CPU so it will sort by Ascending or Descending order.
Check which is taking the CPU?
Rollback/reinstall the older drivers and see if it helps as well.