Powering down PC resets BIOS

Hi guys, weird issue here and hoping someone has any ideas to why.

I typically remove power from my PC whenever I go out of town due to power outages that sometimes plague my area (yes, I have a UPS, still…). Down time here was 3 days.

Anyway, after restoring power and booting the PC there’s usually no issues. However, this last time, upon powering up I noticed the BIOS had reset to its default settings – XMP disabled (I always enable), splash screen enabled (always disable), fast startup disabled (usually enabled), as well as a few other areas.

I don't think this is a CMOS battery issue as both BIOS clock and date maintained the correct time and date.

Anyone see this before? BTW this is a Gigabyte Z390 Aorus Xtreme. See system specs. Also not overclocking.

Hmmm.... mine isn't the only post from PC custom Builds and Overclocking that could be moved to Drivers and Hardware.

@Berton. Yeah, I've got a spare batteries. And I've actually changed one before because I got the same issue some months back. If fact I even removed the battery to clear the CMOS. Yet months later the same weird issue.

As for an UPS, as I said, I've got one, a darn good one at that. Still with all the quick on/off power outages my area gets, I don't like leaving my PC's powered on during these phases and I'm away from home.

Anyway Gigabyte finally released the new i9-9900KS BIOS so I'm about to give it a try since they also say it has a new structure design.

Thanks.

Kyhi said:

there is usually a BIOS setting to prevent the PC from restarting after a power failure

Yes, power off after power failure or something like that. Anyway while that could work. My main issue is having any power going to the PC. It's why I shut off the master PS switch.

Anyway I'm more interested in why the BIOS got reset after the PC was completely powered down and booted back up days later? Never seen that one before.

That is the BIOS/UEFI settings battery. It is either a faulty battery or the contacts in the battery holder.
I have a number of items powered by CR2032 batteries and bad contacts is the main reason why some of them loose power un expectedly.

I clean both the holder contacts and the battery itself. Carefully putting the battery back such that no finger marks are on the battery in the contacts area.
Also checking the battery for voltage with an analogue multimeter.

The clock is now synced with a time server so a slow clock is no longer an indicator of a poor/dying CMOS battery.

It is most likely the CMOS battery. A new one is c. 3.2V. My desktop PC plays up if the voltage drops below 2.8V even though the date / time is correct.

Kyhi said:

But shutting off the Master Power Supply Switch - you are also shutting off the Standby Power.
Thus Draining the CMOS Battery

Please -re-read the first post. I already said all power, so yeah, standby power. That said, this is nothing new as I've been doing that for years whenever I go out of town. This is the first board I've seen reset a BIOS after a complete (no power) shutdown.

And again, if the battery was draining the clock would also be affected, especially after 3 days. CMOS batteries lasts a long time even without power. But, as I stated earlier, this is a new battery.

At any rate I'm going to completely power down the system tonight and see if I can duplicated the issue. I'll also call Gigabyte and ask them about this to see what they have to say.