Yeah pretty sure all setting are fine. It appears this PC has two modes; functioning (24k score) and borked (18k score) and no idea what isn't working correctly and what triggers it.
Do you frequent dodgy websites that’s ladened with malware? Do you have any cracked or hacked DLL programmes? Do you have any pre-activated programmes or even windows? Do you have Av and malware scanner? Might be worth a scan to root out any crap.
performance degradation overtime sounds like malware to me. But could also be driver related as NVidia updates their driver very frequently so might worth an update with clean install option.
Ran malwarebytes and spybot - everything is clean. I'm fortunately old enough now that all of my software is legit. This was a completely new build, blank SSD that I install (Legit) Windows on.
I don't think this is degradation over time. It was initially fine, then went really bad. Did everything clean from scratch, including BIOS, and it fixed itself completely. Then suddenly it's gone really bad again - from a 24k 3DMark score to 18k without any indication of what happened.
I think this coincides with my secondary monitor seeming to go pop. I was kinda waiting for it to die, but as it stopped functioning and suddenly my performance hit the floor again i'm inclined to believe this is my GPU messing up.
There's also an actual issue that isn't performance-based that seems to point to my GPU - my new, functioning monitor is having the signal reset when alt-tabbing out of borderless applications. This could be an issue with the games but as it literally started happening at the same time as this I highly doubt it.
I was thinking faulty mobo, so BIOS makes sense to me at least.
So happy for you mate, it's a horrible experience!
Unfortunately back in not-fixed territory with this.