5950x on Asrock X370 Killer SLI/ac

Not recommended, but it will works.

I'm running a 5900x in the same board.
Two issues I've encountered.

1) VRMs are "fine" for the either 5900x or 5950x, however the heatsinks are not. The VRM with the 5900x running Prime95 will exceed 100C over time. It runs and does not fail, but a 5950x would push that even further. This is only if completely maxed out using tests (small FFT) that drive the power target up a lot. For normal operation day to day, all core with certain operations, even gaming, either processor would be fine on this board.
2) Trying to run four sticks of 16GB 3200Mhz CL16 ram. Under 7.03 beta BIOS, I would get boot looping even with default 2133 memory settings but was able to manually set the XMP with one stick, insert remaining 3, and cleanly boot from then on with 64GB and XMP settings. 7.10 released BIOS no longer supports that and boot loops with 64GB regardless of what timings and speed I try. Works fine with two sticks. Disappointed in that change in BIOS. Even two sticks at default BIOS 2133 settings boot loops. I always have to use only one to enter BIOS, then set XMP, boot to windows, shutdown, and finally add the second stick. This boots reliably from then until a BIOS upgrade that resets the memory settings back to non-XMP. The I need to repeat the process. Odd that 2133 won't boot with more than one stick and unfortunate that 4 sticks no longer support; at least my memory modules 4xOLOy same part.