It should be 10 or 15c above ambient temperatures, and I doubt 70 will have any negative effects. From what I have read the estimate from the Intel guy is pretty conservative. I have hard of people going over 100c without damage to a processor.
I definitely wouldn't advise trying to see how high it will go without damage, but in any event 70 should be OK.
- Edit - I just wanted to say you may want to take a look at your computer's cooling setup. A few simple changes or a few cheap fans can often make a 10 - 15c change in temperatures.
You're kidding right? The rated tcase is 72.6C given by intel at 95w tdp which is one of the highest for any cpu. http://ark.intel.com/products/53446 Intel does a lot of testing to determine safe temp and wouldn't have a rep stating an estimate. Some will say it's safe to get up to ~80C with SB when stress testing but only because stress tests give unrealistic workloads creating more heat than normal. Normal temps would never hit that and constantly being above ~80C will definitely degrade the cpu. Tjmax is 98C and is most likely the auto shut off temp. At about 150C smoke will come off your cpu. There are plenty of youtube vids if you would like to see that.
mine gets 53C at max and I have the same proccessor( it has a T at the end but it should be simmilar). definately do something about it because that can lower the life of your CPU. When mine is idle it is about 27C which is about room temp. I have a cool master fan and heat sink which was stock with my computer. I recently cleaned out all the dust so your computer might be full of dust blocking the heat sink and covering the fan. I would highly recomend you do something about it. either get a new heat sink and fan, clean the inside, or check the overall escape of air through your PC. Mine has two fans to expell air outside and vents to let air in.