6600k Overclock question

[TwiXxiN]

So i have a nice stable overclock @4.6, v1325, temps during games average 54 but can go to 60, and during stresstest with prime95 around 76. But sometimes openning small apps cause cpu temp spikes from 33 (average idle temp) to 55 in a milisecond. When i am playing games temps average around 54 but can go to 60 for a second then go back, but sometimes during loading screens they can even spike higher like 65/70 then go back to 54-60. Sometimes hwinfo says it went to 70, should i be worried or is this normal, my friend did the installation for me so, could it be lack of paste that is causing all these spikes or cooler not properly seated or something?
While full underload stressing, temps are the same without any spikes.
Specs:
6600k 4.6@

390x non clocked

D15 noctua new cooler installed it few days ago

16gb ram
 

[jiyeon]

Micro-spikes are normal as far as I'm aware. My 8600K clocked at 4.4GHz 1.2V is idle 30°C and will sometimes spike to 40°C for literally a millisecond and come back down to 30°C.

[AnTicXz]

no problems here

[EPPHO]

Looks normal to me