I have a Maximus VI Impact board and when I gave the stock cooler a decent tightening, I got Post 55 error and PC wouldnt boot. The nearest ram slot to the cooler would be out of action. I did end up getting it to work as apparently the cause was the cooler being too tight. Fast forward to a new cooler (Zalman CNPS8900) and again same problem if reasonably tight, Post 55 error. I had to spread the paste instead of doing a pea application leave the top righ screw closest to the ram slot looser than the others. This was a trial error and had to remove the cooler about 15 times or so for the PC to boot and show decent temps. Now that it boots, it would be idle around 32 then fluctuate to 47 then down again. This never happened when I first tested it outside the case, had it decently screwed in, it would be 31 idle without fluctuating.
TLDR; why in the world cant I tighten the cooler like Ive seen others do with the same cooler or board? I spent hours to get it to boot with a decent temp
Windows 10 Pro x64 | Asus Maximus VI Impact | Pentium G3258 | MSI GTX 950 | 8GB DDR3-1833
Tightening the cooler too tight can put uneven pressure on the cpu socket pins, good job figuring out the problem. Make sure all the screws have even tension on them. You want the cpu cooler snug not tight.
Your temps look good as it is though, that's how I apply the thermal compound like you did using the spread method. 🙂