I replied to sakiv's post. His issue is to do with turbo boost. Way to fix it is change cooling profile from Balanced which is default to Quiet it makes the turbo boost and fan noise more conservative while not effecting temps. Do this Bios change first.
Boot your NUC. let it load everything and wait five minutes. Make sure nothing is open ie no triangles under your dock icons right click and close everything. Make sure to have rehabmans fakesmc hwmontioring kexts in the kexts/other folder so you can see cpu and other temps. download them from latest file here. Drag the hardware monitoring app into applications folder.
bitbucket.org
If your base temps are at idol 35 to 40 celcius then your temps are ok. You will get spikes in temp up to 95 celcius if browsing the web etc that's normal. If that is ok then your problem is possiblly hardware related ie memory related but worth making sure base temps are ok first.