• Guest, The rules for the P & N subforum have been updated to prohibit "ad hominem" or personal attacks against other posters. See the full details in the post "Politics and News Rules & Guidelines."

What happens if I clear CMOS when running the computer?

steimm

Senior member
Feb 26, 2001
310
1
0
Might seem to be a stupid question, but what happens if I accidently would clear CMOS when the computer is up and running?
 
  • Like
Reactions: Dankbongripz420

Jeeper94

Senior member
Mar 6, 2005
371
0
76
Originally posted by: steimm
Might seem to be a stupid question, but what happens if I accidently would clear CMOS when the computer is up and running?
Just how do you accidentally clear the CMOS when the computer is up & running? :confused:

No, I don't know the answer to your question, sorry.
 

steimm

Senior member
Feb 26, 2001
310
1
0
I haven't done that - I'm just wondering what would happen if I did that.

I'm just thinking there is room for another product on the market...
 

evilharp

Senior member
Aug 19, 2005
426
0
0
Originally posted by: steimm
Might seem to be a stupid question, but what happens if I accidently would clear CMOS when the computer is up and running?
I don't think anyone has ever accidentally done it. I'd imagine that there could be various results on a hardware or software level.

My tip to you: Don't do it.
 

1Dark1Sharigan1

Golden Member
Oct 5, 2005
1,466
0
0
Not a good idea since you should unplug all your power connectors from your motherboard before clearing CMOS . . . there's a reason for that . . . ;)
 

imported_toot

Member
Jan 6, 2005
52
0
0
I'm not sure it's even possible.. Usually you put a jumper in the right place and when you next turn it on, it clears it then. I don't think removing the battery would clear it either, while it's switched on.. You'd have to switch it off for a while.

But hey, if you wanna try it.. :p I think if you did somehow manage it, it _might_ not affect anything until you tried to reboot it..
 

steimm

Senior member
Feb 26, 2001
310
1
0
Well there is surely a risk to CLRCMOS without removing all the cables, but that is something that I never do. I have always cleared CMOS with power cable connected to PSU but of course with the computer turned off.

And I sure do understand that it is no good idea to clear CMOS while it is running, but I was just curious if someone knows what would happen. I haven't tried it yet, but what can really happen?

- Crash boom bang - everything goes black? All the stuff inside the computer destroyed for all future use?
- Crash boom bang - everything goes black, but it would work after a cold boot again but w/ risk for BIOS is crashed?
- Nothing at all until you reboot and BIOS is destroyed?
- Nothing at all until you reboot and BIOS-settings is back to original?
- Nothing at all?
 

steimm

Senior member
Feb 26, 2001
310
1
0
by the way, I have done several "hot flash" of BIOS and that is no problem - but that might not have anything to do with CMOS - or?
 

bob4432

Lifer
Sep 6, 2003
11,571
16
81
Originally posted by: toot
I'm not sure it's even possible.. Usually you put a jumper in the right place and when you next turn it on, it clears it then. I don't think removing the battery would clear it either, while it's switched on.. You'd have to switch it off for a while.

But hey, if you wanna try it.. :p I think if you did somehow manage it, it _might_ not affect anything until you tried to reboot it..
no you do not turn it on with the cmos jumper in the clear position. you turn off your machine, disconnect all power from the machine and 30seconds. then you move the jumper over to the clear position and wait 30seconds. then put it back to the normal position, reconnect power and go.
 
  • Like
Reactions: BadThad

severtki

Member
Apr 9, 2003
177
1
71
Originally posted by: eplebnista
Originally posted by: evilharp
Originally posted by: steimm
Might seem to be a stupid question, but what happens if I accidently would clear CMOS when the computer is up and running?

My tip to you: Don't do it.
I concur!
But hey -- if you do, make a video of it and share with us!

... I've always wondered what would happen if you slammed your transmission into Rev while going 55... Anyone want to try and find out?
 
  • Like
Reactions: Thunder 57

steimm

Senior member
Feb 26, 2001
310
1
0
Originally posted by: severtki
Originally posted by: eplebnista
Originally posted by: evilharp
Originally posted by: steimm
Might seem to be a stupid question, but what happens if I accidently would clear CMOS when the computer is up and running?

My tip to you: Don't do it.
I concur!
But hey -- if you do, make a video of it and share with us!

... I've always wondered what would happen if you slammed your transmission into Rev while going 55... Anyone want to try and find out?
lol - I understand the point - as I have stated, but I thought that someone in here actually knew... But don't compare mechanics with electronics - I don't think that's really fair.

I have a reason to ask this, but before I do anything I'd like to know if there really is current on the three pins for CLR_CMOS. Ok, I know it might differ between the brands and models.

I don't really understand why it would happen anything at all. BIOS and CMOS is not used (or?) when I'm in Windows-mode.

 

Concillian

Diamond Member
May 26, 2004
3,755
8
81
Originally posted by: steimm
Might seem to be a stupid question, but what happens if I accidently would clear CMOS when the computer is up and running?
Probably nothing.

I have hotflashed BIOS before and in doing so you actually remove the BIOS chip and replace it with another (while the computer is in use). Doesn't seem to hurt anything.

I think when it's running, the important parts of the BIOS are moved to RAM.
 

NotquiteanooB

Senior member
Apr 14, 2005
362
0
71
Same results as slamming that auto trannie into reverse at 55mph. NOTHING GOOD will happen to be sure. Only difference ... your mobo is cheaper than a transmission.
 

The Linuxator

Banned
Jun 13, 2005
3,121
0
0
I beleive you might corrupt your BIOS if it isn't protected enough from these "intentional accidents "go ahead and do it but don't come back to the forums crying about your BIOS / MOBO.
But if you still have the urge to do it, get some old cheapo sub $ 50 PC from Ebay and do all kinds of crazy expirements like I used to do.
No matter what happens leave your main rig alone, got the hint ;)
 

steimm

Senior member
Feb 26, 2001
310
1
0
I sure got the hint ;-)

But back to business, what it is REALLY going to happen? There is a lot ppl that "knows" but is it anyone that really KNOWS?
 

steimm

Senior member
Feb 26, 2001
310
1
0
Originally posted by: NotquiteanooB
Same results as slamming that auto trannie into reverse at 55mph. NOTHING GOOD will happen to be sure. Only difference ... your mobo is cheaper than a transmission.

Are you 100% sure of that?
 

bob4432

Lifer
Sep 6, 2003
11,571
16
81
Originally posted by: steimm
I sure got the hint ;-)

But back to business, what it is REALLY going to happen? There is a lot ppl that "knows" but is it anyone that really KNOWS?
nobody around here stooopid enough to do this. go to another forum and ask there
 

doc2345

Member
Jun 29, 2005
191
0
0
Originally posted by: steimm
I sure got the hint ;-)

But back to business, what it is REALLY going to happen? There is a lot ppl that "knows" but is it anyone that really KNOWS?
How can this be ?back to business?? This whole thread is asinine. Why not just fess up? Reboot the damn box and let us know what happens! Geeezzzz, what a waste of time and bandwidth.
 

Peter

Elite Member
Oct 15, 1999
9,640
0
0
The CMOS RAM is only fed by the battery when there is no other source of power. Even in ATX "off" mode, it's fed by the power supply through the +5Vstandby rail.

The "Clear CMOS" jumper has the battery current run through it. When you pull it or set it to the "clear" position, what you're actually doing is disconnect the battery.

So, if you move the "CMOS Clear" jumper while the system is on a (standby or fully) powered ATX PSU, absolutely nothing would happen to CMOS RAM contents. All that remains is the risk of an ESD zap ;)

(Disclaimer: The above is true for typical mainboard implementations. Some might have the jumper in the resulting power feed to CMOS, and some others might always run the CMOS RAM on battery. YMMV.)
 

The Linuxator

Banned
Jun 13, 2005
3,121
0
0
Originally posted by: doc2345
Originally posted by: steimm
I sure got the hint ;-)

But back to business, what it is REALLY going to happen? There is a lot ppl that "knows" but is it anyone that really KNOWS?
How can this be ?back to business?? This whole thread is asinine. Why not just fess up? Reboot the damn box and let us know what happens! Geeezzzz, what a waste of time and bandwidth.
:laugh:
 

steimm

Senior member
Feb 26, 2001
310
1
0
Originally posted by: Peter
The CMOS RAM is only fed by the battery when there is no other source of power. Even in ATX "off" mode, it's fed by the power supply through the +5Vstandby rail.

The "Clear CMOS" jumper has the battery current run through it. When you pull it or set it to the "clear" position, what you're actually doing is disconnect the battery.

So, if you move the "CMOS Clear" jumper while the system is on a (standby or fully) powered ATX PSU, absolutely nothing would happen to CMOS RAM contents. All that remains is the risk of an ESD zap ;)

(Disclaimer: The above is true for typical mainboard implementations. Some might have the jumper in the resulting power feed to CMOS, and some others might always run the CMOS RAM on battery. YMMV.)
Thx for a great reply!

 

Zap

Elite Member
Oct 13, 1999
22,378
2
0
Originally posted by: steimm
by the way, I have done several "hot flash" of BIOS and that is no problem - but that might not have anything to do with CMOS - or?
That kind of stuff happens when the CMOS hits menopause...

J/K

I've done that before. Way back in the day there used to be information on how to do that on Shuttle's web site.

Peter's explanation was pretty clear, but what I don't get is why someone didn't just try it. I was about ready to walk down to the garage and pick out a spare board to try it reading down the thread until I got to Peter's post.
 

ASK THE COMMUNITY

TRENDING THREADS