Demo: I think any temperature is safe as long as you're not thermal throttling and your computer is stable. Intel CPUs seem to run reliably at very high temperatures. The whole purpose of going to multiple on chip digital thermal sensors was so Intel could accurately monitor the hottest point on the core which allows users to run their chips hotter without thermal throttling kicking in.

When you read the documentation, Intel is proud of this fact. They're proud that they were able to boost TJMax by 10C from the original B2/B3 generation to the second gen G0 series like your Q6600. If doing this led to a lot of processors going ka-boom and the RMA numbers went way up then they would have lowered TJMax.

The Core i7 runs hot as hell when they are pushed hard but Intel left TJMax at 100C. I've seen lots of screen shots of people running them reliably at a core temperature of 80C to 90C and I haven't heard of a single report of a damaged CPU because of this. Intel doesn't seem to worry too much about high core temperatures so as long as I'm running stable, I don't worry either.