Unique slowing issue

[pat227]

Ok so everytime I log into SoD my char. is fine for about 20-30minutes -- everything runs smoothly and i zone very fast. After about 30min, everything in game slows 5 times its regular speed. This lasts for about 3-5mintues and goes back to normal after that. then another 20 minutes pass and it happends again for another 3-5min then fixes. There are no gaps between these time incruments and it happends throughout my gameplay. My lag/PL bar stays green the entire time this happens so im guessing PL is not the answer. This has been happening for a while now and it seems to be getting more frequent. Also sometimes the game will speed up 5 times its regular speed and wont fix until i close SoD out and reboot it. On rare occasions I will be able to play and none of this happens at all.
ANY IDEAS what could be going on? Any ideas on a fix?
THANKS

 

[zutfen]

When was the last time you took a can of compressed air to your CPU heatsink?
Check it for "electronic dust" build-up. If Air isn't circulating across the heatsink fins properly it can cause symptoms similar to what you're describing; the CPU heats up to a "danger" level, then scales back on its performance for a bit to let itself cool off. Once it does, it's back to full power, and your framerate goes back to normal.

It's a stab in the dark, but it's a starting point. Give it a look.