Very odd boot behavior on three identical x399 Taichi/Threadripper 2990WX builds.

[jawknee530]

This last week I built three identical builds.

• Threadripper 2990WX
• ASRock X399 Taichi sTR4 : 3.30 Bios
• G.SKILL Trident Z RGB (For AMD) 32GB F4-3200C14Q-32GTZRX: 3200 14-14-14-34 XMP
• EVGA SuperNOVA 1300 G2
• SAMSUNG 970 EVO
• Dual Nvidia Quadro P1000s in PCIe slots 1 and 4 (the 2 x16 slots)

The odd issue is that every time I boot any of the three machines after they've lost access to power it takes three tries.
1st: lights come on, fans spin up, then it cuts off after just a few seconds
2nd: everything comes up, Dr Debug starts cycling through it's thing, then everything cuts off after maybe 15 seconds
3rd: boots properly
This only happens after a fully cold boot where the machines has been unplugged or the psu switch has been flipped off. The machines all boot normally after this first little dance. This happens whether the ram is at 2133 stock or under the XMP profile at 3200.
BIOS Settings:

• CPU at stock frequency and voltages
• SMT disabled
• Precision Boos Overdrive disabled
• SVM Mode disabled
• IOMMU disabled
• All other settings default

I get the same behavior regardless of these settings, these are just the current ones.

 

[Ketchup]

Does this occur with a standard shutdown, or only with hard power off? If you try to turn it back on (power button) with power supply off or cable disconnected, count to 10 or so, then power it up normally, does it come up correctly?

 

[denis280]

Does this occur with a standard shutdown, or only with hard power off? If you try to turn it back on (power button) with power supply off or cable disconnected, count to 10 or so, then power it up normally, does it come up correctly?

+1 and what kind of psu is running those 3 pc.yes i know. me and my darn psu

 

[H T C]

I don't have any TR systems but what OP describes is actually quite similar to what i was getting when i started my system using RAM @ 3200 after it was shut down for a long period.It also happened when i changed something in the BIOS with RAM @ 3200 and then attempted to re-enter BIOS after rebooting: it started booting and shut down a few seconds after. Then it repeated this two move times before loading BIOS defaults, by which time it booted properly (though it took a bit longer to boot when it did so). I stopped this from happening by putting the RAM @ 3000 instead of 3200 so i figure the issue is RAM instability.

Since OP also says it happens with RAM @ 2133, it could be a different problem but, since it's symptoms are similar, i thought i would suggest a slight bump in RAM voltages might do the trick.

My board also happens to be a TaiChi but it's X370, not X399.

 

[RLGL]

Is the memory on the QVL list? If not it may be the cause of your issue.