Question Intermittent Desktop Lag - CPU throttle or PSU/Motherboard issue?

[SamVimes]

Thanks in advance for any help.

Issue: Lately, I've noticed a severe fps drop while manoeuvring around my desktop (opening tabs in Chrome, opening applications, etc.). This isn't the first time. I ran into this issue a couple of times over the last 3-4 months but now it's consistently every day, ~ 3-4 times a day. The framerate stutters significantly for a good 10 or so seconds, my mouse is moving across the screen like a bad stop-motion movie. I haven't really noticed it while playing games, although I have been on an indie game kick lately so nothing super demanding. From what I can tell, the PSU or motherboard failing or something is throttling the CPU, but I can't seem to narrow it down.

Specs:
MSI MS-7C83
AMD RX 480
Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz 2.90 GHz
16GB RAM
Windows 10 Pro 64 Version 21H2 (OS 19044.2728)

Troubleshooting/Info: I am certainly not an expert, but here's as far as I got

• Ran a virus scan (Malwarebytes Free), and nothing was detected
• Ran Intel Processor Diagnostic Tool, no issues found
• Ran a stress test (2 mins long) OCCT Power Test, no issues found
• No timestamps from errors or warnings from Event Viewer that correlate with when I experience the issue
• No processes appear to be tying up the CPU
• Report from HWiNFO64 while the issue was ongoing. I tried marking the rows where I suspected it was happening in shades of orange, but I couldn't really make much out of it.
• Here is a screenshot of Afterburner graphs while the issue was ongoing. It happened twice (marked in red as #1 and #2). CPU/GPU temperatures appear fine? But the clock speed and power are dipping
  

 

[rgd1101]

how full is the ssd?

 

[SamVimes]

Not exceptionally full: 17.5 GB free of 118 GB