Maximum GPU & CPU Temps? Running Fan Control Software

Hello,

Does anyone have an opinion on what the maximum safe temperatures for the GPU and CPU can be and still operate safely? I have been running some flight simulation software on my iMac 27 inch, and recently the GPU burned out. It actually burned out while watching some videos on YouTube, but I had frequently been flying my simulator over the past few weeks and the fans were reving up pretty high during flight sessions. There were no obstructions to the intake or outflow vents. The folks at the Apple Store think it's a fluke, but I'm not feeling warm and fuzzy about it and I am worried it might happen again.

I looked at some software that lets you automatically and manually operate the cooling fans in the computer. I first tried running another application called SMC Fan Control, but I was never able to get it to launch on my screen. I can see it running my processes under Activity Monitor, but I don't seem to be able to find a Control Panel window and it doesn't show up in the Finder or dock after I launch it.

The software discussed in the link below also gives you the temperature readings on the CPU heatsink internal hard disk and DVD drive, and GPU, and lets you set a maximum desired temperature, which then automatically adjusts the fan speeds. This led me to wondering what are the safe temperatures that are safe to operate at without having to worry about turning anything out again.

In this thread linked below, the more comprehensive software called iMac Fan Control by Derman Enterprises requires the user to make modifications in Terminal. I'm not that comfortable messing with terminal commands, and after I tried to follow the instructions, it did not look the same as described. I chickened out and aborted. The SSD Fan Control software is an easy install, but does not provide as much customization nor does it provide the GPU temperature information I am looking for.

http://forums.macrumors.com/showthread.php?t=1156571

I hope someone can help me! Thank you!

Ron