FR did good last night in FSO but I took the side cover off and put a box fan pushing fresh air into the case . CPU must be getting hot .
That really does sound like a heat issue.
www.cpuid.com/softwares/hwmonitor.html is another one similar to what Bustr was suggesting.
Just download it and run it, leaving it running while you're playing AH. It can tell you when things are getting warmer than they should. I only suggest this one because I've never used the one Bustr recommended, but it's a bit simpler to use basically 'turn on, look at window to see if stuff is out of line.' They should show you if it's a heat issue.
Temps on the indicators it shows should be below 60 in most cases.
Wiley.