Also happens to me on Windows 7. Didn't happen before, on a fresh install.
(i5 M520 on a Thinkpad T510)
I also keep seeing new creeping processes that I haven't seen before, all the time. At first I thought I was getting senile but then new processes kept popping up every month or two. But that's ok, it's getting wiped soon.
not sure if this will work
Get a laptop mat with a fan. Seems like you've tried everything else.
After some testing....
I've installed the drivers from lenovo's site.
a few strange things changed...
I've had a constant temps and frames as a positive.
but I had constant 5 frames 
this was the problem!
I've tested the adapter from a friend of mine who also has an lenovo.
the temps didn't seem to matter..
with his power cord I had constand frames, no drops, no problems.
Thanks anyways guys!
Just an other example how important decent power is.
