Methox,
My configuration follows:
Phanteks Enthoo 719 case
Gigabyte Aorus Xtreme
G.Skill 3600 16-16-16-36 4x16GB
Custom Loop:
EK 480mm XE rad and EK reservoir (running ~1.5L fluid in total)
Noctua PWM-3000 fans throughout 8x120mm 2x140mm: 140s are blowing down over the VRM and block from the top, Rad is front mounted with rad fans blowing outward to front and 4x fans bringing in fresh from side.
Smart fan roughly linear from 20% below 30c to 100% at 60c
Alphacool block
Thermal Grizzly Kryonaut compound (spread via business card method)
All voltages stock/auto, "most" parameters stock, except enforcing XMP and memory voltage at 1.35. Haven't done any subtiming tuning yet...
System is running Hyper-V/VBS and a couple of low load VMs under Windows 10, so nothing is ever truly idle, but it's close.
Idle temperatures are in the low 30c range and at full load (Prime95 continuous with 2 workloads of 8 cores each), I get to the high 50c range on average over many hours. Ambient temperature in the house is low 70s F. HWInfo shows all cores clocked at ~4.3 GHz, with some variance. My primary goal here is long term stability...
With that said, and realizing I built for more headroom to bring in a water cooled 3xxx when Nvidia finally gets around to it, it seems like you're a more than a little high at idle.
Based on your initial statement, you haven't ramped up core voltage or attempted to overclock to squeeze out more performance or for stability?
Early AMD BIOS had a bunch of problems with over voltage and thermal issues with the 3900x, even at idle, long before release of the 3950x. You seem to indicate that you have updated to the latest...
Assuming your air flow is solid, I'd start out making sure that your AIO is running a performance profile for the pump, vice a quiet profile, I'd consider increasing the ramp-up of your fans, at least those driving the AIO rad and I'd consider popping the AIO off and verifying that you have a solid, but thin, layer of paste covering the entire processor. As you likely know, the AMD chiplets are spread out more than they would be for an Intel Core i processor... From everything I've read and observed, the 3950x is easier to cool than previous generation 8 core platforms.
If this doesn't solve the problem, recommend that you use a tool like HWInfo64 sensors to capture the running settings initialized by the BIOS to ensure that they aren't, in fact, applying excessive voltage. There are several settings that I locked down on my board to bring stability from boot to boot.
If you don't get the issues solved by the weekend, I'll post my own readings to give you a set of numbers to compare to...
