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Clear CMOS not working?

Oromit
Level 7
Hello,

I got the Crosshair IV Hero AM4 mainboard recently, and so far it's running great.
While setting up and and testing the max possible RAM speed(Ended up at DDR4-2666 for a 32GB 2 Module Dual-Rank kit), I ended up in a situation where it wouldn't POST anymore.

For some weird reason, the Clear CMOS button on the back of it didn't seem to have any effect though. All the lights go out on the board, but it still wouldn't boot again, even after turning off and back on again on its own multiple times on the next boot.
I eventually got it to boot up again, by trying various combinations of removing system power, pushing Clear CMOS and booting via the safe boot button on the mainboard.
To my surprise when I got back into the BIOS, all my settings, even the too high RAM frequency, was still there, completely unchanged, but it booted in safe-mode, with low RAM speed. The only thing that actually got reset was the system time, no other setting was affected.
Just pushing the safe boot button on its own also doesn't work. Only the combination of some of the things I did worked out in the end.

Is this intended? It makes fiddling with settings rather scary if there is no clear and always working way to recover.
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12 REPLIES 12

Arne_Saknussemm
Level 40
The function of safe boot is exactly that...to boot with previous settings retained but in safe mode..i.e. settings not applied but default settings.

Clear CMOS is supposed to be done with power removed from board...i.e. a short while after switching off PSU...then press clear CMOS....but sounds like it's not working as intended or you are not waiting long enough with power removed from board.

Go easy for now...some boards are bricking with lots of resets and button pushes

Raja
Level 13
I did hear a rumor that some users may not be waiting for the board to update fully following a UEFI update. After the initial flash completes, the system restarts, and it can take a few minutes for onboard controllers to be updated. If the user resets things during that process, it may be leading to some of the problems. Not sure about that, as I'd need to see it first hand.

Yeah, I'll definitely not touch it again for now. It's running stable, and I already confirmed that the RAM does not work on any higher setting.
The odd thing is that safeboot also doesn't seem to work without the board being powered down right before. I'll make sure to switch off the PSU in the future if it ever happens again.

Yes, when Updating the BIOS, the board boots into a screen where it displays "Updating UEFI..." on screen. I did wait for that to happen when I updated to the current beta.

Majesty-nl
Level 7
The Clear CMOS is also working without powering off in my sitiation:

When i tried for increasing the RAM freq, i did get a fail post loop every time,
so when that happends, im pressing it for 2-3 sec, and then its shuts off the system, then pressing the power button,
after 5-10 sec im live with fabric defaults!

Majesty-nl wrote:
im pressing it for 2-3 sec, and then its shuts off the system, then pressing the power button,
after 5-10 sec im live with fabric defaults!


Yes, that's about what I'd expect. But besides resetting the system clock to 2011 or something, all the settings stay right where they are.
Haven't tried it with turned off system power yet, and won't fiddle with it anymore for now.

JustinThyme
Level 13
2-3 seconds is usually not enough on the clear CMOS. This is the same as pullling the battery without pulling the battery. Its best done cold and hold it in for at least 30 seconds.



“Two things are infinite: the universe and human stupidity, I'm not sure about the former” ~ Albert Einstein

Majesty-nl
Level 7
definitly it works with 2-3 seconds on all my boards. You cant compare it with the old and fashion battery way :).. its just an trigger to clear it...

Majesty-nl wrote:
definitly it works with 2-3 seconds on all my boards. You cant compare it with the old and fashion battery way :).. its just an trigger to clear it...


Works for me too. Boot fail at QCode 55? Clear CMOS button and power on again for default settings worked all the time.

Arne_Saknussemm
Level 40
The fact that clear CMOS often "works" without disconnecting power does not invalidate the advice trying to be passed on here.

Clear CMOS is best done with no power connected to board...and after sufficient time has been allowed for power to drain from board...."cold" as it has been put.

I put "works" because I have done this often enough to know that it often doesn't...

Sometimes leaving the board with no battery and no power over night is the only way to shift some weird problems...

Popping the button in while the board is powered is like wiping your nose with your hand...your mother will tell you to get a tissue and do it properly...