[SOLVED] Pc Boot Mystery

[ttower2020]

I built a PC for a friends mother. I am having a strange problem now, and here is how it went.
Specs -
Ryzen 5 3600
Cooler Master Hyper 212 Evo
2x8 3600MHz Corsair Vengeance
Asus Prime B450M-A/CSM
EVGA 550W non-modular PSU
500GB WD 2.5 SSD
AMD HD 5450/GTX 1660 Super (explained later)

All of the PC parts arrived, except the GPU, so I put together the system, and reused an old GPU, the HD 5450 that was not being used anywhere else. This system was used for two weeks, while the GPU was being shipped. There was apparently an occasional White Screen issue, which I thought was likely the old GPU. Today, the new GPU arrived, the GTX 1660 Super. I installed the GPU, and booted the PC. I installed the Drivers off the Nvidia website. Everything was normal. However when I built the PC, I forgot to set the RAM speed, so I went into the BIOS and made three changes. I set RAM speed to 3600MHz, Turned on Fast Boot, and set POST delay timer to 1 second. I went to the exit options, and selected "Save and Reset". I thought Reset seemed an odd wording, but there was no other save and quit option, so I figured it was fine (is it?). The PC never displayed again. When I plug in a monitor, the monitor comes out of standby mode, since it has been plugged in, but goes to sleep. I tried changing the GPU back to the old one, nothing changed. I reset CMOS battery, which did nothing. I tried pulling out one, then the other, sticks of RAM, and nothing changed. I reseated the GPU, which changed nothing. I made sure that the PSU cables were plugged in all the way.

There was one thing I noticed which was wrong. When I first installed the GTX 1660S, which needs an 8 pin PSU cable, the 6 pin went in, but the 2 pin (6+2), was not locked in, and was therefore not plugged in all the way. I replugged it correctly, and that did not fix the issue. When I boot the PC, all the lights and fans come on, and it seems normal. There is just no display. I even tried unplugging the PC while on, which I would never do, in order to try to get the "Safe Mode" to trigger, which boots the PC back up in normal boot, instead of fast boot. This did nothing. I assumed the motherboard was capable of 3600MHz RAM, and nothing on Amazon contradicts this. This and higher options was available in the BIOS.

I have nothing left to try. I do not know what is wrong, and dont know where to look next. I think the PSU is having a problem, due to that plug not being in all the way, and the new GPU using so much more power. The other thing is that maybe the motherboard or BIOS got corrupted or locked up somehow? I welcome any suggestion.

The other problem I have is that other than the HD 5450, there are no available replacement parts at the house, and my compatible parts will take over 1.5 hours to get. She also does not want her new PC to leave her house, since it cost her so much.

 

[ttower2020]

I convinced her to let me bring the PC back to my house, so I was able to solve the problem, and I know what happened.
When I was looking for PC parts for her to order, I found a motherboard that was the best deal I could find at the time, due to CV supply issues. This board happened to support 3600 MHz RAM, so that is what I had her order, since it was only $5 or so more than 3200 MHz. Well, and I forgot this, her order got cancelled since she missed the payment, and she needed to reorder all the parts. Three of the parts the she ordered were no longer available, so she ordered the closest thing she could find. This was fine, and she ordered all the right components, but the motherboard she got only supports 3200 MHz, apparently.

When I got home, that was my prime suspect, since that was the biggest thing I changed the BIOS before the issues started. I swapped her 3600 MHz stick, with a stick from my PC, which was 3200 MHz. This forced the BIOS to boot using a slower speed it was capable of. It booted after a CMOS clear like normal. I changed the BIOS settings to run at 3200 only, and then swapped her 3600 back in. It ran fine. Out of curiosity, I changed the RAM back to 3600 in the BIOS, and the same thing happened, which confirmed my suspicion. Doing the same thing, clear CMOS, replace RAM with slower stick to boot system. Set speed lower, and swap back the faster RAM. The system is now running fine. I just think it is odd the Asus lets their motherboards be set to a RAM speed they cant run at, which causes the system to seemingly fully lockup, with no workaround other than getting another set of RAM.

 

[rocktalkrock]

"Save and Reset" is the correct option.
Was the computer unplugged when you reset the CMOS battery?
When you tried booting with 1 stick of RAM was it located in slot DIMM_A2?

 

[ttower2020]

I realized later that if I exit the Advanced Mode, then F10 is a "Save and Exit", which I used, which didnt seem to have an effect, so I think you are right there.

I think it was unplugged, I know I unplugged it a few times, so that was probably one of them, though I cannot say for sure. I know I unplugged it after I got it back to my house while doing the CMOS reset.

I did not change the slots the RAM were in, just unplugged one of them, then put it back and took out the other. One of them was in slot 2, the other was in 4. When I was using my stick of 3200 later, I was putting that stick in slot 2.