I've noticed some games do it and some games don't. Recently upgraded to running 2 4850's. I've read that Radeons do it more than Geforces. You are open to spending ~120$ for 6670 AND ~210$ for 560ti? I spent only 70$ for my 2nd card, so was no brainer compared to buying just 1 better card, though IF i had the $$$ would have gone for 560ti.