Hello, first my parts

Using an MSI z170a gaming M5 mobo Intel i7 7700k (recently replaced an i5 5600) MSI GTX 970 8gb ram 650W semi modular PSU

So, Ive submitted posts before asking for advice, this issue has been happening for a few months now. Basically, my computer will lose about 80% of its processing power, getting terrible framerates in games, using 100% processing power on occasions where it absolutely should have no issues, and having all around terrible User BenchMark scores. Initially it even dropped my processor score on Windows Performance index from a 7.something to a 4.8, almost as if it identified the issue as a change in hardware.

UserBenchmarks: Game 25%, Desk 24%, Work 19% CPU: Intel Core i7-7700K - 18% GPU: Nvidia GTX 970 - 48.9% SSD: Crucial BX200 240GB - 57% HDD: Seagate Barracuda 7200.14 1TB - 85.6% RAM: G.SKILL Ripjaws V DDR4 2400 C15 2x4GB - 45.5% MBD: MSI Z170A GAMING M5 (MS-7977)

When its working, my scores look more like this:

UserBenchmarks: Game 69%, Desk 87%, Work 60% CPU: Intel Core i7-7700K - 99.1% GPU: Nvidia GTX 970 - 68.6% SSD: Crucial BX200 240GB - 70% HDD: Seagate Barracuda 7200.14 1TB - 87.5% RAM: G.SKILL Ripjaws V DDR4 2400 C15 2x4GB - 74.7% MBD: MSI Z170A GAMING M5 (MS-7977)

Temps are always fine using MSI Afterburner to monitor the stats, and GPU usage is normal. Because processing power seemed to be the main problem, I thought I could have had a faulty processor. After trying everything else I could think to do software wise, and after reseating the processor twice, I finally bought a new processor. Everything worked without issue for a couple weeks until yesterday when the problem started again. Now I know it isnt a processor issue. Everything from BIOS to Windows is totally updated, and technically my computer does everything it is supposed to do, except sometimes it cant handle any relatively intensive task (mid range video game, Windows Movie maker, benchmark software) without getting unnaturally slow.

As far as when it happens, and for how long. It's totally random as far as I can comprehend. When it first started, it was constantly impaired for a few days, then it would work randomly for maybe a few hours, maybe a few days before having issues again. Currently it has not been working correctly for 2 days, checking a few times a day.

I have no idea where to turn next, and I'm curious if the Motherboard isn't the issue. While the processing ability seems to be the main issue, Userbenchmark shows deficits system wide, and so this makes me think that perhaps it's the motherboard acting up? I am truly not an expert, and am way beyond knowing what to possibly do.

I just want my computer back, man...

Edit: Forgot to mention, I checked for buldged capacitors and any other scratches or scuffs on the mobo a while back, and didn't find anything that stood out as problematic. I don't know how obvious a buldged capacitor necessarily has to be in order to be an issue, however.