I just recently put this rig together. Few hours ago actually
Antec 650 Earthwatts PSU
EVGA P55 V
G.SKILL ECO Series 4GB (2 x 2GB) Model F3-10666CL8D-4GBECO
A DVD drive and a Harddrive
Got a cool Antec tricool fan in there too
Anyway. Everything booted okay, and everything runs well. BUT things got a little hot earlier. I'm using CoreTemp to monitor CPU temp. CPU idled at about 42C. Doing normal tasks it was running around 50-60. When running windows experience index it hit 70. I thought all was good, idle CPU temps where a bit high but yeah.
So i started playing Final Fantasy 14 on it. It was playing around 70C which i thought was okay. After about an hour though it ran to the 80's. And after playing some cutscenes i saw the temps in the upper 90's. One of the cores hit 98C.
That's when i decided to shut it off.
I took out the heatsink to reapply and make sure the Arctic Silver 5 was on there evenly, and it was all good. And i noticed that my fan was blowing air away from the heatsink, iunno why. Thought that was weird. I guess air suction cools it down a bit but i thought air blowing across it would be better. So i positioned the heatsink to where it sucks air from one of my other fans while that fan is blowing air on it. After doing that, reapplying the paste and repositioning everything i'm looking at temps of
Core 0: 37
Core 1: 32
Core 2: 38
Core 3: 31
Temps are more uneven then before but they are cooler. I dare try Final Fantasy again, though i will but. How on earth did my CPU get that high after being all good for a few hours? Is Final Fantasy 14 that CPU intensive?
My temps seem to fluctuate pretty fast btw. like once it was on 98C while on Final Fantasy after i closed it 6 seconds later it was back at 66C And like even now i would go on and off from 38-44 in a matter of seconds then back down to 38-37 once whatever task i have stops loading.
I think i did good doing all that, my temps playing the game havn't gone higher then 60C. Even with full screen and high settings which i didn't have on before. Will keep updated if i get high temps again. As of now i think it's all good.
Sounds like initially it was a mounting issue. You might consider upgrading the heatsink tho, a Hyper 212 Plus is only slightly more expensive but it's a really great cooler. Alternatively, buy a 2nd fan for the cooler.
The other thing is, what speed is your cooler's fan running? If it's plugged into the CPU mobo fan socket, as it should be, you should go into the BIOS and set the fan from there. Should be in something like power management, hardware config or something along those lines. In the menu it should display the CPU temp, as well as all the fans connected to the mobo and their speeds. With the CPU fan, you should be able to set a temp like 50C or 60C, and set the fan thresholds as 10% and 100%. That way at idle the fan is nice and quiet, and then when you are putting work through the CPU and temps go up, the fan will speed up to 100% speed and cool it down.
You can also control it through Speed Fan if you want, but I found that program kind of sucks... just my opinion.
As for temp fluctuation, it's always fast. And core temps are rarely equal. At idle mine are about 2-3C apart and under load it's as much as 5-6C difference. And yeah, put load it takes seconds to get to high temps and then take the load off and it takes seconds to go back to idle temps.