Question i7-6700K temperature issues


Dec 17, 2016
So, I have an i7-6700K with a EVO 212 cooler in a Antec P280 case with 3 exhaust fans as well as the PSU acting as an exhaust fan as well. It also has a GTX 980 Ti which is stock OC so that puts out a good amount of heat as well. This system was built in late 2015 as I had the CPU on pre-order. In general, the system hasn't been very well maintained, especially in the past 2 years or so and has been through several moves, including a cross country one.

I recently took my side panel off while the system was powered on recently (forget the exact reason why) and I noticed that the CPU fan was completely seized up and have no idea how long it has been like this. I'm a bit surprised the system didn't warn me of this, but it didn't. Luckily I had a spare system unused that had the same cooler, so I took the fan off it and installed it on my heatsink and was good to go.

However, I've noticed my system my system has been running hotter than normal lately, not sure if it's from the stress of newer games or that I've upgraded to a 1440P monitor from a 1080P monitor... but I've noticed during games that the sides of the case gets warm to the touch and the air coming out of the exhaust is extremely hot. I took the system outside and blew out all the dust and checked the other fans in the system, including the GPU, and everything seems normal, however, cleaning it out didn't seem to make a difference.

Tonight I decided to do a pretty hardcore stress test with HWMonitor open while I took a nap. I left Prime95 set to small FFTS and left the Heaven benchmark running in a loop on max settings which put both, my CPU and GPU at 100% load. I woke up an hour or so later and noticed the following in HWMonitor:

CPU Max: 99 C
CPU Min: 34 C
CPU Clock Max: 4200 Mhz
CPU Clock Min: 800 Mhz (I have power saving disable, so it's always running at 4000 Mhz, so this must be thermal throttling)
GPU Max: 80 C
GPU Min: 54 C
DIMM1 Max: 58 C
DIMM1 Min: 38 C
DIMM2 Max: 62 C
DIMM2 Min: 40 C

We'll say the room temp was probably 24 C around this time. I know that's warm, but living in the Deep South USA, that's what I'm used to.

Obviously I Heaven and Prime95 and allowed the system to cool down and just performed "normal" tasks... YouTube, E-Mail, etc. Nothing CPU or GPU intensive. I left HWMonitor on during this time and noticed my idle CPU temps were a bit all over the place... bouncing between min 30's to mid/high 40's within seconds, like when I'm loading a new YouTube video, etc. I decided to run Prime95 again and watch the temps as soon as I started it, and it went from 35-40 C to 75-80 C in a matter of seconds. It never seemed to "level off", kept climbing up to 85 C after 5-10 minutes so I shut it off. CPU fan was working as I heard it spin up as soon as I hit start in Prime95.

So, this is my theory... I'm thinking that after 5+ years, and an unknown amount of time with the CPU fan dead, that the thermal paste is probably dried up/hardened. So, this is my planned course of action at the moment:

  1. Purchase a replacement/new Hyper 212 Evo (while the fan I have now works normally, I'm expecting it to seize up like my last one as the bearing is making noise, very little, but it's there)
  2. Apply new thermal paste obviously
  3. Replace the 3 case fans (that came with the case, so I'm unsure of brand, etc. They all work, but a bearing is starting to fail in one of the top ones I believe) with Noctua's. Expensive, but I have no plans on getting rid of this case anytime soon.
  4. Add two Noctua intake fans on the front on the case to help pull cool air in.
  5. Relocate from under desk/on floor to on top of desk in an open area for better airflow.
Any other suggestions aside from the above? Thanks in advance.
You seem to know what you're doing well enough. The only thing I'd add is to leave the front door off the case. Any front fan(s) may struggle to move air in with the door on and all those drive bays are not helping. As long as there's nothing blocking the front or back of the case you shouldn't need to move it off the floor. Heat rises so the coolest air in the room should be nearest the floor. The CPU and GPU have fans to keep them cool. The job of case fans is to keep air moving through the case. You might consider moving the top fans to the front as intakes and leave the top slots empty. Hot air will easily vent out the top on its own. Replacing the paste and moving the fans might be all you need to do.
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