Question PC only posts on second attempt

[ciddh]

Specs at bottom.

When I power this PC on, I see lights on the motherboard and hear fans spinning, but no display. It'll just sit there in that state without any display or indication that it's managed to POST. If I hold the power button down until lights/fans all stop, give it a few seconds, then try again, it'll POST/boot to Windows 10 just fine. Once I'm in Windows 10, everything will function just fine until I shut down or restart. If I shut down or restart, I'll have to go through the whole "try again" routine again to get it back up. Basically, whenever I start this PC, I have to do it twice.

Once in a blue moon, it WILL POST/boot successfully with just one attempt. I have an RGB keyboard and mouse, and I know it's going to start okay if I see those lights come on within about 3-4 seconds of pressing the power button. This is rare, but it will occasionally start just fine with only one attempt. So there is a bit of inconsistency here.

Sometimes, once I get it running on my second attempt, it'll take me to a "The system has POSTed in safe mode." warning, where I can press F1 to enter setup (where I don't really see anything jumping out at me as the problem). At this point, I can either press F1 to enter setup and use the "Exit without changes" option, or I can just press ctrl+alt+del, and the system will start normally. It doesn't always do this and will usually just boot Windows 10 normally.

This started after I updated the BIOS for the motherboard (which I did about a month ago). I normally take an "if it ain't broke, don't fix it" approach when it comes to BIOS updates, but I was installing a new SSD, fresh installing Windows 10, cleaning things out, etc, so I decided to install the BIOS update while I was at it (not to mention the release notes for that BIOS update promised "improved system stability"). Problem has been consistent (aside from the whole "once in a blue moon, it starts fine with just one attempt" thing) since then.

I've found a few posts (here and elsewhere) where people mention similar issues, but none of the fixes I've found really seem to apply to me. One of them fixed it by identifying and replacing a bad stick of RAM (granted, memory tests aren't always perfect, but I've tested mine and found no issues), a couple fixed it by clearing CMOS (done that, didn't help). I'm not sure if this motherboard supports rolling back the BIOS, but it did just occur to me that I could try that if it does. Was wondering if anyone else had any other ideas first though.

Specs:

Case: Fractal Design Meshify C
PSU: EVGA Supernova 750W G3
Motherboard: ASUS ROG Crosshair VIII Formula (4402 BIOS)
Cooling: NZXT Kraken X3
CPU: AMD Ryzen 9 3950X
GPU: MSI GeForce RTX 2060 Super 8GB
RAM: 64GB G.Skill F4-3600C16 (4x16GB)
OS: Windows 10 Pro 22H2
SSD (OS): 2TB WD Black SN850x
Secondary SSD: 2TB WD Blue SN550
Monitor 1: HP S340C (DisplayPort)
Monitor 2: ASUS VS238 (HDMI)
UPS: APC BR1500MS2 1500VA
Keyboard: Logitech G910 Orion Spectrum
Mouse: Corsair Nightsword RGB

I built this system back in 2020. The only recent hardware changes were the SN850x SSD (replaced a 1TB Sabrent Rocket that I was using before) and the UPS. Everything else listed hasn't changed in the last 3 years or so. I did install the SSD at the same time as the BIOS update, but I kind of doubt the SSD is the problem here since I'm not seeing any other indications of problems with it (and WD's monitoring software says it's healthy).

 

[Grobe]

My guess: Your UPS cannot handle inrush current.

If you use only the mains supply (remove the ups) - will the problem persist ?

 

[GarrettL]

This isn't the first post I've seen on this forum where someone updated the BIOS and then had booting issues when trying to use 4 sticks of RAM.

Have you tried setting your RAM to the default of 2133MHz?

Try only two sticks of RAM in the A2 and B2 slots and see if the issue persists. Try at default speed and also at 3600MHz.

It is very difficult to get 4 sticks of RAM to run on AMD cpu's above the default memory speed as the memory controller is on the cpu itself.

 

[ciddh]

This isn't the first post I've seen on this forum where someone updated the BIOS and then had booting issues when trying to use 4 sticks of RAM.

Have you tried setting your RAM to the default of 2133MHz?

Try only two sticks of RAM in the A2 and B2 slots and see if the issue persists. Try at default speed and also at 3600MHz.

It is very difficult to get 4 sticks of RAM to run on AMD cpu's above the default memory speed as the memory controller is on the cpu itself.

Setting to 3600MHz might've fixed it. It defaults to "Auto" (which shows as 2133MHz). After I changed it to 3600, I went through a couple of shutdowns/startups without error. That didn't occur to me, for some reason. Will run with that for a couple of days and update here if problem occurs again. Thanks.

@Grobe The UPS is recent, but I actually bought it shortly _after_ the problem started occurring, so I don't think that's it (I should've mentioned that in my OP, my bad).