I just installed an i5 3570k, even though I don't intend to overclock. It should be going at 3.4ghz, but I'm not sure about the temperature.
Idle is mid to high 30's. Within seconds of exiting a game, the temp drops right back to low levels, so that's not very worrisome. But I don't know about mid-70's from playing games. I set the cpu fan to high in the BIOS, but I don't have a controller or program, so I don't know how strong it's really going. It's a Cooler Master Hyper TX3, and numerous reviews say their CPU isn't even going over 60C, and I'm getting over 70C. I thought it was touching the CPU, but I have no way to make sure and it's not really going to go down any further. I could try applying the thermal paste to the base instead of the cpu.
HWMonitor right after maybe 30-40 minutes of Team Fortress 2:
Hi mate , alright since you've said you don't intend to overclock. I'd give you first advice is to reduce your voltage in your bios as manufactures have the voltage higher than they can use. That will reduce your temperatures a bit. Secondly clean your CPU & surface of the cooler with Isopropyl or alcohol which is at least 90% pure. I got hold of 99% pure isopropyl which is amazing to clean the surface of my CPU etc. After that use a pea size drop in the center of the CPU and get the heatsink to squash it and spread it out. Then run Prime95 & cure the thermal paste and leave the pc with Prime95 running for a while and turn all the fans on as high as you can etc. Once that works check your temperatures and reply back to me !