So, I have been running a NUC7i7BNH for roughly one year and I've noticed a significant decrease in performance lately when it comes to performing simple tasks, up to the point where I'm starting to doubt the longevity of the machine.
As for a benchmark example, a couple of months ago I was able to play Grand Theft Auto V at acceptable settings without any issues, but now I don't even dare to try anymore since I've had the machine crash due to sudden heat after just a couple of minutes. But I think there's a different issue, because even when I strictly run Chrome and use a single tab to stream some video or whatever the CPU core temperature remains at a fairly constant 65-70 degrees, which is way higher than it should be. The machine also gets pretty noisy. I checked the core temperature through a diagnostics tool, HWiNFO64.
The case is in a relatively dust-free area (it stands on a wooden desk which is not in a carpeted area), I clean pretty meticulously once or twice a week and I do not live in an area that is normally affected by extreme heat (outside temperature is roughly 20-21 degrees Celsius at the moment).
I disassembled the case to check for dust that might clog any parts but there was nothing as far as I could tell. I didn't go as far as to disconnect the motherboard seeing as I don't want to mess up any warranty, but I ran a virus scan and a malware scan (just to rule out hidden mining software or something like that taking up power) and both came out perfectly clean.
BIOS is currently at version 0079, I run a 64 bit version of Windows 10, I have 16 gigabytes of RAM and the machine features a 500GB SSD. There's no significantly heavy software idling in the background as far as I can tell, so I am at a loss here. Any suggestions as to a solution would be more than welcome, and please feel free to ask for additional details you think might be relevant, I'd happily provide those.
The dust usually is accumulating on the board upper (invisible) side, where the blower is installed. So in order to undust this NUC you have to remove board. You may try to blow air from air duster, trough the vent holes.