Just last evening I had a number of unusual things happen while working on an image using TG3; most notably the populator you see while it indicates instances, upon completion, it does not just blink off - but rather fades off in increments. Also, I'll see something that looks like a colored bar code flash on; then go off quickly. Then, after closing TG3, I went into the Internet and it froze. Other weird things like my screen would produce a dialog box when I clicked on anything (normally what I would see if I right clicked on it). And a few other things as well. All of this gets me thinking it could be my Nvidia card being affected by high heat.
Today, everything seems OK. I'm beginning to think the issue is overheating. I installed the 'Core Temp' software which displays numbers. Example: The higher numbers means you are running cool. As the numbers get lower, you are approaching higher heat. When idling, my cool number is in the low 80s; while rendering, the higher heat numbers are down to 52.
I have placed a small portable fan behind my tower to help disperse the exhaust from it.