Have you stress testes the whole system to see if the PSU won't shut itself off because of heat?
I'm just wondering if the single fan also gives it enough breathing air.
The Nightjar 450 PSU is the component in my system that I'm least worried about in terms of overheating as it is apparently well designed to run passively (see, for example,
this reddit post and the Kitguru review linked therein explaining how efficient it is).
However, my system
was doing automatic restarts during CSGO (I suspected due to insufficient power delivery) so I'm guessing that the Nightjar 450 couldn't handle 9900K and EVGA 2080 Ti SC under full load with my motherboard (Asus Strix 390-i) at stock speeds/voltages. So I
undervolted the 9900K and
undervolted the 2080 Ti using the values for GPU and CPU suggested by Optimum Tech. So far I am able to get full system stability (without automatic shutdown/reboots/BSOD) running Unigen Heaven 4.0/CSGO/CODMW/Warzone just by
only undervolting the RTX 2080 Ti which significantly reduced power consumption and GPU thermals. However, I was getting BSOD when undervolting the 9900K, so I reverted the 9900K back to automatic/stock voltages (because I needed stability in order to do my work from home). I haven't had time yet to figure out optimal undervolting settings for my 9900K and/or there's something I'm not doing right.
I installed the CR-80EH last night as shown in
build pics here. The CR-80EH will
not fit in the Asus Strix 390-i motherboard, unless the metal I/O shroud (which functions as a heatsink for the VRM modules and also shields EMI) is removed
and low profile memory is used. I'm sad that I have to forgo my Corsair Dominator Special Editions (CL14, 3200 MHz) in order to get the CR-80EH to fit so I bought these
Samsung ICs (also CL14) and removed their heatspreaders (they actually have better timings than the Dominator SEs).
I thought that I could achieve decent thermals with the NCASE (v6.1) which has a moderate amount of ventilation holes and thought that a negative pressure setup would work well (without the the dust filters). But with stock/automatic 9900K voltages/frequencies I'm still getting 90+ deg C for CPU under load in CODMW (even with case panels removed) which is unacceptable. I'm able to get OK thermals (~70 deg C) in CSGO and Unigen Heaven 4.0 which is acceptable to me, but I think CODMW puts the heaviest practical gaming stress test that I need to pass. Also, the slim fans (which only fit with CR-80EH) run
way too loud under load for my taste (especially the Noctua 92mm A9x14 -not sure if my A9x14 is a dud). Honestly I'm not sure whether I was achieving better thermals with the Alpine Passive or the CR-80EH.
So my attempts at running a 9900K inside an NCASE M1 with a semi-passive heatsink have yet failed. I'm considering
deliding my 9900K.
Or I might just cave and just settle with an NH-C14S and call it quits...
Will update my next step which is to replace GPU cooler after I finally decide on CPU heatsink.