I'm after some tips on where to start trying to find the cause of intermittent lag running BT5 R3 on a dell Latitude E6410. Its installed on the local HDD with a duel boot to windows 8, which is fine. I had the normal kernel panic with the Intel GPU but that was an easy fix after searching the forums but I'm not finding much on here for speed issues.

I've watched my processes for a while and can't see anything in there but it does seem like a process as it comes and goes, sometimes wicd will jump to the top around the same time but never taking all the system process. My main symptom is one minute I'm typing in the console, or any application and everything is fine then all of a sudden it'll lag and words are appearing a few seconds after being typed.

It does the same thing from a live CD version too. MD5 has been checked for consistency and that's fine.

Any pointers where to look are greatly appreciated.