OK i've had absolute fun and games today updating the build with the new 4 arctic P12 fans that arrived yesterday. So here goes...
My specs:
Asus B550i
5800x
Mugen 5 Revb (RGB)
Crucial Ballistix 3600mhz CL16
3080 FE*
Adata 2TB NVMe
SF750
4x P12 fans
*note: i am running an undervolt here so it only needs 981Mv to hit 1950mhz. I used this guide, but my card needed a touch more juice than it recommended:
https://www.youtube.com/watch?v=FqpfYTi43TE&t=193s&ab_channel=OptimumTech
My room is about 23C.
So, I removed the 92mm fan behind the CPU cooler, and installed the 4 P12's (checking arrows, etc). I switched the CPU fan to exhaust.
Temps for my CPU were rubbish (hitting 90C instantly on cinebench, running 80C in games). Before it ran mid 70C's in games and 86/87C in cinebench.
Temps for my 3080 FE were abysmal. Hitting 80C in games, which it usually ran at about 72C before.
I assumed it was an issue with the differential fan speeds and creating turbulence. So I turned off the bottom fans and it went back to 70C (a few degree improvement from 72C due to i'm assuming better top fans now).
I was pretty dissapointed with these temps, and I opened my case to switch my CPU fan direction back to intake, and take the bottom 2 fans out.
However, when i was taking them out i noticed i had accidentally installed the bottom fans backwards... they were exhausting... what a doughnut!
No idea how i did this as I very specifically checked the directions.
So switched them to intake, and CPU back to intake. GPU temps are now amazing, in the same test where i went from 80C (wrong direction fans), to 70C (fans off), the 3080 now peaked about 56C with 2 bottom intake fans.
I stressed it longer when i got a 100% GPU consumption part on cyberpunk and let it run for a good while, and it runs at 60C (this was with the undervolt, and applying custom fan curve to be a touch more aggresive - still inaudible behind the already quiet P12s). Great result.
For the CPU, back as intakes it went from 86C to eventuially 90C in cinebench, but thats normal for a 5800x. Gaming it was now at 75C in cyberpunk, down 5C. Again - normal temps.
However, i saw this adjustment to PBO to run a smaller boost in this thread:
https://www.reddit.com/r/Amd/comments/kfpele/5800x_adjusting_ppttdcedc_limits_on_pbo_got_me/
So i set my mobo PBO settings to PPT = 120, TDC = 75 and EDC = 110.
Now in cinebench i hit an all core boost of ~4300 MHz, but with a max temp of 75C! Speeds in multicore cinebench will be a touch less, but marginal. Single core should be identical as all we're doing is reducing the total power for boosting essentially.
When gaming in cyberpunk in same test area as before, (downtown area using all cores) i hit 72C. And performance was perceivebly identical, i couldn't tell any difference looking at the FPS counter.
So overall very happy now. I absolutely recommend bottom fans for a 3080 FE in the NR200p, i got a 15C drop in a like for like test!
Pics of the final build, and more in this link:
https://imgur.com/gallery/BtN7DwE