I wrote RealTemp so users could get some reasonably accurate temps without having to invest in an IR gun. Most of the processors that are supposedly "running hot", are being reported by temperature software that is using the wrong TjMax. I was hoping you could run my test and post your results. Someone with an L2 did this once and showed that TjMax=85C looks reasonable but that was quite a few pages ago. I'm waiting for some summer weather to see if the delta between core temp and room temp at idle remains about the same.

Given the cooler you're using, your room temperature and your core voltage, 60C while running Prime is reasonable while 75C is not likely.