My i5 with the stock cooler has idle temps anywhere between 35 and 42 degrees Celsius. I believe that's normal. However, when I stress it, either with prime95 or intensive gaming, the temperatures go up to the mid to upper 80's and sometimes even hit 90. I think that's technically within the safe operating range, and the cpu doesn't throttle down or make the computer shut down or restart or anything, but it has been worrying me. There is some dust in the the heatsink which I will take off and clean out, but I'm just wondering if these temperatures are normal and I'm worrying for nothing. Also, since I'll be taking the heatsink off should I just go ahead and purchase an after market cooler or is the stock cooler just fine? I hear good things about the coolermaster hyper 212 evo. Is that the best one in that price range? Thanks in advance for any help!