It also seems to be more be of the internet that seems to cause it for me as if I was going to fast for it. Looking through images or pages and switching between apps causes it to. For me the GPU core is working fine it's the memory clock that seems to "stick" for me.
I just did a reinstall of the 13.11 with the firewall and everything turned off to see if that will do something.
I do agree that it seems like something it giving the card a false instruction that causes it to go into a loop. Maybe it's having problems digesting? After a while it works fine and then it will go buggy until one of those things I mentioned is done as if there was a large chunk of information going to it that it can't dump.
EDIT: yep I was going fine until a few mins ago when I watched a youtube video and now the memory won't clock back down.
01:13 PM by