I've long since (2010) replaced my Windows installations with Gentoo Linux, so this is like a memory from very distant worlds...

If I do recall things correct-like, at some point I had a very similar, if not identical issue which may have been related to hardware monitoring software of a particular motherboard, running on Windows 7. So, if you have anything like that installed and running, I'd try getting rid of them for testing purposes at least.

I'd also check the drive health using 'smartmontools', even if it may be unlikely to be the source of the problem.

That being said, another thing that I suspect of causing me similar issues at that time (though less frequent, not every few seconds), was a Western Digital Green drive that can exhibit rather brain-dead behaviour by parking their heads very often for power-saving purposes. However, I never really tested that theory since I had moved away from Windows by the time the idea occurred to me...

Luckily said feature can be turned off, but the count for one of my drives was already well beyond 500k at the time I noticed, and they're rated for 300k (not that the drive has failed yet at the time of writing... <knocks on wood>).

One thing I'd also add to the other suggestions, is try to monitor the resources used, particularly CPU and I/O, and see if you can spot any correlation with them and the timing of the stutters. I'm not sure how well this is possible with the Windows 10 monitoring thingies.