Over the last few weeks I noticed that my otherwise silent pc started making fan noise. At first it was not very audible, so I thought nothing of it, but it gradually became worse. I then checked out the temps and found my CPU to idle at around 65 degrees Celsius. This was odd, as it had always idled in the lower 30ies. I always clean dust of my PC regularly and had actually done so just a couple of days prior to checking the temps, so I know it's not related to dust.
I then checked if the cooler (stock cooler) was properly seated. It seemed to be so, but I removed it and placed it back on (with some new thermal paste) anyway just to be sure. This time the temperature became even worse! Around 70-75 degrees Celsius at desktop after booting, gradually turning hotter upwards 85 degrees. At this point I shut down the pc, went out to a shop and bought a Coolermaster 212 Hyper Evo cooler. Even if it was not cooler-related (which it appeared to be at the time) at least I would have a good cooler, I thought.
New cooler installed, the temperatures dropped to around 50c stable. This was much better, but still not at all optimal, especially considering I had a new (very good) cooler and fresh thermal paste.
Thinking something was perhaps wrong with my sensors, I updated my bios. This reduced the temps by around 10 degrees down to 40-42c. Again, better but not desired at all, especially considering that the PC was still noisy. It would also make no sense for it to be the BIOS since I bought the motherboard and CPU together and have used them together (with the same BIOS version) ever since the beginning with no prior issues.
Some days later I upgraded my monitor to a 1440p monitor. This put the temps back up to 50-55c idle. My GPU temp also increased a bit, so I assume this temperature increase is normal and irrelevant (but still worth mentioning).
So here I am with a CPU that idles at 50-55C with a great cooler and no dust in the machine. I feel like I've tried everything now.
I've had this exact same PC setup for quite some time with no changes at all (apart from the new monitor) since I assembled the system: Intel i7 2600k
16 GB DDR3 RAM
Intel DP67BG motherboard
120gb SSD drive and 2 TB normal HDD
560 ti GPU
Windows 8.1 (upgraded from 8.0 in mid-december).
So I've tried the following with little to no success:
Installing a new cooler
New thermal paste
It also can't be airflow related, as I've had the exact same airflow the entire time, even when the CPU idled at 30 C.
All other components run fine and cool as supposed to. This only affects the CPU and I experience no other problems apart from the very annoying fan noise. The motherboard also has a fine temperature of 40C idle despite being very much affected by the CPU heat.
Hi again, I ran Prime95 as you suggested. Taskmanager showed 100% CPU load.
The results are actually surprisingly good. The CPU doesn't even go above 60 degrees Celsius during testing (I made sure to try all the different tests to be sure I picked the right one). The fan speed didn't change at all. At least not enough for it to be an audibly noticeable change. No artifacts, glitches or any other problems either.
While this probably means my CPU is perfectly usable, I am left to wonder the following:
1) Why are the idle temperatures almost identical to the load temps? A difference of 5-10 C seems weird and not right... Especially since this was not always the case. It still idles at higher temperatures with the new (good) cooler than with the previous (bad) stock one.
2) Is there a way for me to reduce the fan speed while idle? I can live with the audible noise but if it could be reduced a bit when not under load that would be amazing.
EDIT: Also, my general CPU usage seems to be a bit high... around 60% on desktop after boot. I even try to make sure a lot of bloatware doesn't start on boot. Service: Local System (~20%) and Service: Remote Procedure Call (~20%) and Anti Malware Service (10%) seem to take the most resources.
I found the issue with CPU usage. I went into the Event log and found that my PC produced Error 10016 about 10-25 times A SECOND... I did some googling and found a guide to the issue. It's apparently related to some kind of permission-issue in Windows 8/8.1... I did some registry tweaks and permission tweaks I had absolutely no clue about and just followed blindly, rebooted my PC, and when it booted my CPU usage was back to ~15-20% with a noticeably lower temperature (around 35 idle). The fan is still obnoxiously loud compared to what it used to be, but I'll look into that speedfan thing.