So my sapphire 6870 is probably about 2 years old now. Recently while gaming after any where from a few minutes to an hour games will start to lag and become incredibly choppy. In titan fall for an example. I can usually play 4-5 Attrition matches before it starts to get incredibly choppy. Crysis 3 sometimes will start audio looping then freeze and crash completely sometimes needing a completed reboot.My gpu sometimes idles at 60c according to gpuz. Outside of gaming. Windows is completely fine. I get no artifacts on the screen .Im on windows 8.1 Pro 64bit and Have a AMD fx 4100 , gigabyte 990fxa-ud3 and 8gb of ram. No BSODs at all no error pops up so Ive really got nothing to go on. Just these symptoms. Just wondering if this sound like an overheating gpu?