Question Question on what pressing the CMOS button actually does.

Crom808

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My motherboard: Asus Dark Hero

Hey guys, been searching online and got multiple answers on what the cmos button does when you press it/hold it down


1. It resets your motherboard setting to default settings on your CURRENT bios

2. It resets your motherboard bios version to the FACTORY version

3. I clears your cmos chip to factory settings and version just like when you first got it

Also I have a few more questions please to clear up any confusion:

4. Is there any difference between the following methods of resetting BIOS (clearing CMOS) settings:

a.inside BIOS, using option "Load Optimized Defaults" (or, if applicable, load fail-safe defaults)
b. At the back of the motherboard, pressing , Clear CMOS" button
c. On the motherboard, using the (CLRTC) jumper
d. On the motherboard, reseating (not a typo, for non-english speakers) the CMOS battery
e. Reflashing BIOS using the same version

my last question is:

**5. After flashing a newer, same, or older BIOS, is there a need to load optimized defaults and then start setting everything up from there


Thank you again everyone! I appreciate it!
 
Last edited:

boju

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Clearing Cmos by forming any of those functions when applicable all results the same, it clears the Cmos chip of system parameter data which then once system starts backup will re-enter data from Bios rom into Cmos. Kind of like Bios is the OS and Cmos is ram. Loading Bios defaults usually does just that but not sure if it's always a complete replace of all data across brands. Sometimes resetting Cmos could be done just for piece of mind that after a Bios flash, it's new data completely replaces old.
 
5. just doing a regular BIOS update through motherboard control software will usually leave your current settings intact.
flashing the BIOS manually with a USB stick has almost always reset my BIOS settings to factory defaults.

but, like Colif stated; it can be different depending on the board manufacturer and the specific model of motherboard.

4. Loading Optimized Defaults is not the same as clearing the CMOS.
clearing the CMOS will reset to factory defaults. while Loading Optimized Defaults uses a profile designed to try and get what the designer though of as the best options for your average system.

but again, results can always be different depending on the manufacturer and the model of the board.

also like Colif stated, check the user manual. either get out the manual that came with it or better yet, download the latest PDF version available on the product manufacturer's support page.
 

Crom808

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Thanks for the reply guys.

Okay now I'm confused. Someone on another forum told me this:

"it does not factory reset your BIOS. It just clears out any non default settings and restores them to default on your current bios version, "

"But if you flash your bios to either the same, newer, or older bios, once its flashed, all remnants of the original BIOS on there are gone and overwritten."

Really confused. Does the cmos button function actually factory resets to the factory bios version? Or does it ust resets the CURRENT bios version default setting?
 
Really confused. Does the cmos button function actually factory resets to the factory bios version? Or does it ust resets the CURRENT bios version default setting?
it still depends on the specific motherboard.

but resetting to factory defaults does not mean the same thing as resetting to the original available BIOS version. a board can ship 6 months later with an updated BIOS version but still has "factory defaults" in place.

all that means is that settings are not optimized for any particular use. while Optimized Defaults changes settings to what an average system may get more benefit from.
 

Crom808

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@JohnBonhamsGhost

My Asus dark hero shipped with the first bios version. And I updated to the newest one which is the 3rd version. So pressing the cmos button would put it back to the original bios version that my motherboard had when I gott it? Or would it just reset to the default setting of my CURRENT bios?
 
So pressing the cmos button would put it back to the original bios version that my motherboard had when I gott it? Or would it just reset to the default setting of my CURRENT bios?
will only reset the motherboard's current BIOS settings, not the BIOS version.

if you have a dual BIOS setup, you will have a separate option to flash back and forth between the stored BIOS versions. clearing the CMOS has nothing to do with this option though.

you can load any BIOS version you want onto a USB stick, whether it be older or newer, and flash to that version. but this also has nothing to do with clearing the CMOS or Loading Optimized Defaults.
 

Crom808

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@JohnBonhamsGhost

Thank you very much for that clear answer. Believe it or not, there were conflicting answers online, or I'm just not good at reading comprehension (probably the case)


While I have you here,



Okay what happened was, in the bios ez flash utility, the long progress bar went all the way to 100%, and it said it successfully installed and my system would restart. When it restarted, it went to the black screen with white text

""Bios if updating, Do not shut down or reset the system to prevent system bootup failure."

So it rebooted 2 times to this screen, on the third reboot is when my monitor did not have a signal, so I didn't know what to do. I waited 30 minutes then I pressed the reset button and it booted up one more time to the (Apparently this dram monitor no signal boot thing is a bug for these new asus dark hero boards)

"Bios if updating, Do not shut down or reset the system to prevent system bootup failure." screen

then it went to the bios after that. And I've been able to boot it multiple times without a problem. I haven't installed windows 10 yet as I DON'T know if the bios installed properly or not.


My question is


1. Did it update properly?

2. If we don't know, then can I just flash it with the same bios version so I know it installed properly?

3. Will flashing the bios to the same version safe and won't do anything to the motherboard? Will it be like a fresh Bios version (Where I actually know it completed 100%?)

4. There's a lot of ppl that say flashing your bios to the old, same version isn't safe. I don't know who to believe. So much conflicting answers
 

Colif

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I think only Gigabyte boards have dual bios so which ever bios you put on with a flash will be only version on board.

Dual bios on their boards isn't 2 different bios, its just got a backup copy of current bios so if the pc doesn't boot right due to a corrupt bios, the pc will restart, flash copy onto normal bios and boot from normal again. it never uses the backup.

Some more expensive boards may have 2 BIOS, not sure.
 
when the BIOS screen is loaded check the version number. if that matches the version you installed, it worked.
go ahead and install the OS and your system drivers.

if any major issues develop with drives, devices, or system boots; then you may have a problem but don't fret about it until that arises.
 

boju

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John did answer your question?

when the BIOS screen is loaded check the version number. if that matches the version you installed, it worked.
go ahead and install the OS and your system drivers.

if any major issues develop with drives, devices, or system boots; then you may have a problem but don't fret about it until that arises.
Check version number in Bios is what he said to clarify update.
 

Colif

Win 10 Master
Moderator
"Bios if updating, Do not shut down or reset the system to prevent system bootup failure." screen

then it went to the bios after that. And I've been able to boot it multiple times without a problem. I haven't installed windows 10 yet as I DON'T know if the bios installed properly or not.


My question is


1. Did it update properly?

2. If we don't know, then can I just flash it with the same bios version so I know it installed properly?

3. Will flashing the bios to the same version safe and won't do anything to the motherboard? Will it be like a fresh Bios version (Where I actually know it completed 100%?)

4. There's a lot of ppl that say flashing your bios to the old, same version isn't safe. I don't know who to believe. So much conflicting answers
I had to go out myself

1, see above answer, the bios version on the default screen on bios will show you version installed.
The reason you get different answers is its different for every motherboard/bios version
Some bios updates only work in 1 direction, they might change how the BIOS update process itself works and you can't go back to the previous versions.
If this is your board - https://rog.asus.com/au/motherboards/rog-crosshair/rog-crosshair-viii-dark-hero-model/helpdesk_bios - it is so new that you don't need to worry about it.

the Asus bios update process isn't very informative, it doesn't say its done at end, it just restarts PC. It does tell you to load optimized defaults afterwards though, see page 3-3 - https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/ROG_CROSSHAIR_VIII_DARK_HERO/E17453_ROG_CROSSHAIR_VIII_DARK_HERO_UM_V2_WEB.pdf
you might want to look at page 3-4 as well, Asus Crashfree BIOS.
 

Crom808

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@Colif



Thanks again for your reply. I did go to the motherboard manual website and it said this:


View: https://i.imgur.com/9dwgsZH.png


So what its saying is if it fails or gets corrupted during a flash, it mean that if you can't post/can't get to bios? Because when my screen had no signal after it rebooted to make the third update, I press the reset button and it went back to my bios

Also on #4 what does it mean ? Because when I hit reset I went back to the bio and it seemed normal. I don't know if its corrupted or not. Do I still need to hit F5 to restore to defaults? Like I don't even know if it installed properly or not, that's why I'm trying to decide what to do. Its showing the updated bios and it boots up to bios everytime with no problem (I haven't installed windows 10 yet)
 
without an OS to access, it will go to the BIOS each time.
as i stated before, go ahead and install your OS and system drivers.
you can customize\optimize the BIOS settings after the system is ready to go.

you really seem to be making a big deal out of nothing. you've got no post screen errors, no corrupted images onscreen, etc.
 

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