Necessary or optional: Clearing CMOS after updating BIOS

  • Thread starter Thread starter aether
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A

aether

Per the manufacturers website (ABIT), it states one should clear the
CMOS (by moving the jumper off for a couple seconds) after updating the
BIOS. I never found this necessary in the past, and have updated the
BIOS without doing so. All of the additional features in the new BIOS
are available. Am I potentially harming the computer?

Also, I upped the CPU core voltage to 1.5 from 1.4. This is an AMD 3500
processor. What harm could this cause? It's potential is 1.8, but I
think that's extreme and unnecessary.
 
aether said:
Per the manufacturers website (ABIT), it states one should clear the
CMOS (by moving the jumper off for a couple seconds) after updating the
BIOS. I never found this necessary in the past, and have updated the
BIOS without doing so. All of the additional features in the new BIOS
are available. Am I potentially harming the computer?
Click to expand...
No harm. Some people have problems depending on their hardware. Worst
case you are unable to boot until you clear the bios and sometimes you
must also change to manual jumper settings for at least the first boot.
The German bios flasher has a utility bundled with aflash that clears
the bios without having to use the jumper.
 
I don't think it caused any problem, but since I was having other
issues, I went ahead and cleared it.

It sure is nice to have BIOS flash utilities. Attempting to pry the
little jumper off everytime you tinker with the BIOS is quite annoying!

Thanks
 
Completely unnecessary unless you are noticing a specific problem, such as
radical changes in benchmarks or unusual, new bugs or glitches. It's rare
that a BIOS update will store anything in the CMOS differently than before,
and even rarer that anything will become scrambled during a BIOS update.
 
.... unless you have a gigabyte board where the bios data has been known to
get progressively corrupted as settings are changed!

It is not necessary and is normally done after some bios error has occured
(IE nickers in twist).

I always power off after a successful flas (always flash twice), boot, Load
defaults, then re-enter all settings.
 
aether said:
Per the manufacturers website (ABIT), it states one should clear the
CMOS (by moving the jumper off for a couple seconds) after updating the
BIOS.
Click to expand...

I think the prudent thing to do is assume they have their reasons for
making the recommendation.

I never found this necessary in the past, and have updated the
 
Per the manufacturers website (ABIT), it states one should clear the
CMOS (by moving the jumper off for a couple seconds) after updating the
BIOS. I never found this necessary in the past, and have updated the
BIOS without doing so. All of the additional features in the new BIOS
are available. Am I potentially harming the computer?
Click to expand...

The Advanced Setup in CMOS RAM determine how the chipset registers are
configured. When the BIOS is updated there is no guarantee that the
same memory location in CMOS RAM will control the same chipset
register. The behaviour of the motherboard will then be unpredictable.
I don't know if this scenario occurs in practice, although I suspect
one would need to be careful of third party BIOSes. In any case I
don't envisage any potential for damage, just a harmless black screen.


- Franc Zabkar
 
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