[SOLVED] PC restarts after turning it on and then it works

[opran_dragos]

So, a couple of weeks ago, my pc started to act strange. After it stays off for a long time l, let's say a day, when I start it it restarts and then works(no bios post - sometimes it restarts twice and before the second restart i see the bios splash screen). I tought it was my cs 550 m psu, but i changed it to HX 750w and it does the same thing. Pls help!
Gigabyte z370 gaming k3
I5 8400
16 gb 2666 ram
Gtx 1060 6 gb
Ssd 970 M2
Corsair HX750W
Seagate Baracuda 2Tb

 

[Supahos]

That's usually a sign something is going wrong in bios. Do you have your cpu or ram overclocked?

 

[opran_dragos]

The ram has xmp activated

 

[Supahos]

Revert it to stock and see if there's any difference.

If not maybe replace the cmos battery? Don't expect that to help but they're cheap and easy

 

[opran_dragos]

It's tricky to debug because it does this after it stays off for a while. I updated the bios and it does the sam thing.

 

[Supahos]

I understand, I'll keep an eye out for updates going forward

 

[opran_dragos]

I entered bios a couple a minutes ago and the xmp was disabled, so yeah, it does that with the xmp diasabled

 

[opran_dragos]

I checked the cmos battery with a multimeter and it s ok 3,3V

 

[Supahos]

If the bios is resetting itself that still makes me wonder on the battery. It might have the voltage but not enough power to keep it up overnight.

Xmp shouldn't disable itself unless that battery died and let the BIOS reset

 

[opran_dragos]

Ok, so I'll buy a new battery tomorrow, and before I make the swap I ll check if the bios resets itself over the night. Should I try to start it without gpu, then with each one of the ram sticks?

 

[Supahos]

It "could" be the GPU, but the ram is more likely since the issue is booting.

 

[opran_dragos]

Update: this morning it started with no problem. Last night I cleaned the cmos battery and ram with some contacts cleaner. This afternoon the same restart problem. As soon as I got bios post I checked if the bios reseted and no, it didn't. I got a new battery, but I think the replacement is useless in this conditions.

 

[Supahos]

Most likely it was going to be was just working for something really cheap that might help. Next thing I'd try is updating the bios itself. Could be a bug in it. If it's all the way up to day go back one version

 

[opran_dragos]

Ok, I'll get the previous version and I'll be back in a couple of hours. I'll also check the error LEDs on the mobo while it does its thing. If I do remember well, I think it did the same thing before the bios update.

 

[opran_dragos]

Before I started it again, I removed the GPU and pushed the power button, no problem so far. OK, so I cleaned the GPU s contacts and added it back after some restarts. I'll be back in a couple of days with an update. Thanks for the help Supahos!

 

[opran_dragos]

After some trial and error and half slept nights I think I found the culprit. It seems that a ram slot fails at the inital check-up sometimes. Regarding the gpu - I tried the other, slower, pcie and it does the same thing. Since I moved the ram kit to the second channel it's smooth sailing. I'll buy a mobo buzzer and move the ram to the initial location and se if it beeps. I'll write again when I am sure that the ram is the problem. Many thanks!