When both CPUs are enabled the motherboard gets past 2A code, meaning it's starting to initialize, but immediately resets. Disabling either of the 2 CPUs will make the system work again. Is there some sort off compatibility issue with newer GPUs? I learned to live with SR-2 quirks, but not being able to upgrade GPU sucks. Couple of years ago I tried 290x with my motherboard. That failed completely... At least 570 somewhat works.

Additional question. After overclock i loose a single stick of memory from each cpu. Just noticed that all sticks are recognized if i run just a single cpu at a time.

CPUs: Xeon 5675
GPU: RX 570
BIOS: 080016

nofearek9
are the cpu pins on the motherboard in good condition/clean? 
have you installed latest bios ?

CPU pins are clean and not bent. Motherboard worked with 7990 and v4800 amd GPUs. BIOS is probably up to date. I don't think they have updated in the last couple of years :D. Even though PC boots with only single cpu enabled and rx 570, I'm having trouble installing drivers. Might need to completely clean previous drivers and try again. The GPU was ex-mining card with a custom BIOS. Was getting Error 43, so had patch it with (AMD/ATI Pixel Clock Patcher). It would have been great, cheap upgrade from V4800...

One problem solved, couple to go...

bill1024
Just for the heck of it, try setting the "Low memory gap" setting up to the max.
Can't hurt and maybe it will fix the issue.

I just randomly downclocked(was running 1333 stick at 1866, changed them to 1500) my memory and the gpu started working with both CPUs. Changed the low memory gap to 3G, definitely wont hurt :)

No the question is how far i can push the memory until I will have problems again

Robbanswe
A lot of settings need to be tuned to get 1800mhz working.
Search on evga for SR-2 memory settings.
I think a have uploaded a lot of bios pics :-) 
180xmulti gives u over 1800mhz at 1333 setting
 

Thank you for the images. I'm running 187blck on xeon 5675. This gives me a stable 4.3Ghz. I see you have enabled Intel speedstep. That gives me BSOD, so I have it disabled. Interestingly my uncore only goes to 2666 (20x), while you can go up to 4800 (36x). Not sure if there is any productive benefit in that, but found it weird.

Im running ECC memory, so that's probably why they don't like running 1800 stably. I guess I'm stuck at 1500 for now. Just put the mem frq to 1066.

Robbanswe
Ecc 1800mhz is ok
u get better uncore with the latest bios.
Intel speedstep off is better.
1500mhz is ok.
I use 1066 setting more stable with higher overclock.

Does Uncore improve rendering capabilities?

Robbanswe
Really i dont know, try :-)
uncore help cpu overclocking and faster cpu is faster rendering,

Have you had any trouble with chipset fan? It's my second one failing and im considering just running it with out a fan. The temp are with in spec (65C) with fan they go to (45C) Buying another fan would mean a matter of time until that one will fail

must have a chipset fan.
a have mine at 36 % in bios the lowest rotation really quiet,,, under 36% fan stop working