More or less safe to turn off power supply rocker switch?

[Nicholas Dreyer]

I keep my PC on for at most a few hours a day. After it has powered
down, is it safer to shut off all power to the motherboard using the
toggle switch on the power supply, or is it better to leave it on, or
does it not matter at all?

Thanks for any advice, or pointers to some useful studies on the matter.

Nick

 

[Man-wai Chang to The Door (33600bps)]

I keep my PC on for at most a few hours a day. After it has powered
down, is it safer to shut off all power to the motherboard using the
toggle switch on the power supply, or is it better to leave it on, or
does it not matter at all?

Soft-off still draws electricity. If you worried about fire, shut off
all power.

--
@~@ Might, Courage, Vision, SINCERITY.
/ v \ Simplicity is Beauty! May the Force and Farce be with you!
/( _ )\ (x86_64 Ubuntu 9.10) Linux 2.6.33.2
^ ^ 20:17:01 up 5 days 12:09 2 users load average: 0.00 0.00 0.00
ä¸å€Ÿè²¸! ä¸è©é¨™! ä¸æ´äº¤! ä¸æ‰“交! ä¸æ‰“劫! ä¸è‡ªæ®º! è«‹è€ƒæ…®ç¶œæ´ (CSSA):
http://www.swd.gov.hk/tc/index/site_pubsvc/page_socsecu/sub_addressesa

 

[John McGaw]

Soft-off still draws electricity. If you worried about fire, shut off
all power.

And if you are really really worried, unplug it entirely. No telling when
bad switch karma will catch up with you...

 

[Strobe]

I keep my PC on for at most a few hours a day. After it has powered
down, is it safer to shut off all power to the motherboard using the
toggle switch on the power supply, or is it better to leave it on, or
does it not matter at all?

Thanks for any advice, or pointers to some useful studies on the matter.

For ultimate power economy, use the switch - modern PSUs continue to provide 5v
when the PC is 'off'..

To *really* economise, switch off with a cheap external power strip - it's
cheaper to replace that than a PSU when the switch eventually wears out!

If you live in an area prone to lightning storms, it's safer to actually unplug
the PC when not in use - a nearby lightning strike on the power line can easily
jump over a power switch and *might* fry your PC.

Of course, at most you'll save a few dollars a year...
And many other devices (TVs, microwaves, cable boxes) also suck power when
they're nominally 'off'.

 

[Nicholas Dreyer]

For ultimate power economy, use the switch - modern PSUs continue to
provide 5v when the PC is 'off'..

To *really* economise, switch off with a cheap external power strip -
it's cheaper to replace that than a PSU when the switch eventually wears
out!

If you live in an area prone to lightning storms, it's safer to actually
unplug the PC when not in use - a nearby lightning strike on the power
line can easily jump over a power switch and *might* fry your PC.

Of course, at most you'll save a few dollars a year... And many other
devices (TVs, microwaves, cable boxes) also suck power when they're
nominally 'off'.

Thanks all for the feedback that points to the advantages of complete
power off.

I was leaning that way, but my only question regarding that approach
would be: Is there any risk to the motherboard from regularly turning
back on the low-level 5v "soft power"?

 

[David W. Hodgins]

I was leaning that way, but my only question regarding that approach
would be: Is there any risk to the motherboard from regularly turning
back on the low-level 5v "soft power"?

You will get different answers depending on peoples prior experiences.

My preference is to leave all electronics running 24/7, with
something like boinc running, to keep the cpu at 100% usage, all
of the time.

That way, everything stays at the same temperature.

My cpu (with a 14" fan blowing into the open case) runs at a steady
49C when clean. When it hits 55C, I clean the cpu heatsink, without
having to shut the system down.

My two hard drives run at 36C and 34C. They were running in the
high forties, before I started using the big fan, with the case
cover removed.

While the bearings on my hard drives may fail sooner, the
circuit boards do not undergo any thermal expansion/contraction,
so the rest of the computer should last longer.

As always, make sure all critical data is backed up offsite.

Regards, Dave Hodgins

 

[Massimo]

You will get different answers depending on peoples prior experiences.

My preference is to leave all electronics running 24/7, with
something like boinc running, to keep the cpu at 100% usage, all
of the time.

That way, everything stays at the same temperature.

My cpu (with a 14" fan blowing into the open case) runs at a steady
49C when clean. When it hits 55C, I clean the cpu heatsink, without
having to shut the system down.

My two hard drives run at 36C and 34C. They were running in the
high forties, before I started using the big fan, with the case
cover removed.

While the bearings on my hard drives may fail sooner, the
circuit boards do not undergo any thermal expansion/contraction,
so the rest of the computer should last longer.

As always, make sure all critical data is backed up offsite.

Regards, Dave Hodgins

I cannot believe my eyes reading this posting.
Are you serious?
This will cost you much extra money, only 'to protect the
motherboard', you significantly shorten the lives of your devices and
from the vuepoint of the environment...

Massimo

 

[~misfit~]

Thanks all for the feedback that points to the advantages of complete
power off.

I was leaning that way, but my only question regarding that approach
would be: Is there any risk to the motherboard from regularly turning
back on the low-level 5v "soft power"?

Not so much to the motherboard but there's more stress put on the power
supply as the big capacitors 'fill', there's a big inrush current. In fact
the only times (twice in 15 years) I've had catastrophic failure (BANG!) of
(one of) the large capacitor/s in the PSU was when applying mains power to
it.

There is another consideration. If the machine is turned off at the back, or
unplugged, the small battery on the motherboard that retains BIOS settings
will die more quickly. However they're only a couple bucks (depending on the
brand and where you live).

What could be more of a PITA is if you have custom BIOS settings such as an
'on the edge' overclock or 'just so' RAM timings, or even if you're running
your HDD/s as AHCI (and the default is 'IDE emulation'). Then, when the
battery does go you have to know these settings so that you can re-enter
them when you replace the battery.

 

[Nicholas Dreyer]

I cannot believe my eyes reading this posting. Are you serious?
This will cost you much extra money, only 'to protect the motherboard',
you significantly shorten the lives of your devices and from the
vuepoint of the environment...

Massimo

Yes, I would never want to go through with all that Dave suggests - and
doubt anyone else would, unless they have some extraordinarily valuable
motherboard and hard drive setup - and didn't care about the racket,
expense and environmental consequences of constantly running fans, but to
get back to my unanswered question:

Assuming CPU shutdown is to happen after more or less daily use of a few
hours at most, does daily 5v "soft power" re-energizing of motherboard
via power supply rocker switch prior to reboot add significant, or even
measurable wear and tear on its circuitry?

 

[Nicholas Dreyer]

Not so much to the motherboard but there's more stress put on the power
supply as the big capacitors 'fill', there's a big inrush current. In
fact the only times (twice in 15 years) I've had catastrophic failure
(BANG!) of (one of) the large capacitor/s in the PSU was when applying
mains power to it.

There is another consideration. If the machine is turned off at the
back, or unplugged, the small battery on the motherboard that retains
BIOS settings will die more quickly. However they're only a couple bucks
(depending on the brand and where you live).

What could be more of a PITA is if you have custom BIOS settings such as
an 'on the edge' overclock or 'just so' RAM timings, or even if you're
running your HDD/s as AHCI (and the default is 'IDE emulation'). Then,
when the battery does go you have to know these settings so that you can
re-enter them when you replace the battery.

Ah, what you say here is very interesting to know. It's sounding like
the slight energy consumption of leaving the PSU rocker switch on
permanently is not as bad as the possibility of a blown out PSU from
repeated powering-up, so I will continue to leave it on permanently.

The reason I was focusing on the rocker switch question was because my
last PSU blew after a mere four years with the rocker switch left on all
the time except for occasional cleaning, maintenance and moving: One
day, after CPU shutdown the previous night, nothing would start until
installation of a replacement PSU.

Thanks for sharing all your experiences,

Nick

 

[Nicholas Dreyer]

Yes, I would never want to go through with all that Dave suggests - and
doubt anyone else would, unless they have some extraordinarily valuable
motherboard and hard drive setup - and didn't care about the racket,
expense and environmental consequences of constantly running fans, but
to get back to my unanswered question:

Assuming CPU shutdown is to happen after more or less daily use of a few
hours at most, does daily 5v "soft power" re-energizing of motherboard
via power supply rocker switch prior to reboot add significant, or even
measurable wear and tear on its circuitry?

OK, ~misfit~ just answered this while I was posting the question, so I
will leave the switch on permanently to avoid the strain of on/off
switching on the power supply itself . . . unless of course someone has a
more compelling argument favoring the alternative approach.

Thanks, Nick

 

[Nicholas Dreyer]

... but there is supporting evidence. It depends on the particular
weakness of the entire *system* and by system I also mean the power
grid.

Basically the evidence comes from tracing fault modes, looking at dead
equipment rather than formal testing long term which serves little use -
by the time meaningful data was a accumulated nobody wants to build a
new system with old parts and it would have to be based on the
contemporary tech of the time as merely deciding a "disk drive" is a
"disk drive" is not enough, the designs change too much over the years
to combat failure modes as much as the design budget will allow.

Will it be subject to significant power spikes? IF so then certainly
turning it off at a power strip will reduce # of events seen on average.

Leaving it running tends to be most problematic if it uses poor
capacitors or fans so their lifespan elapses before the viable lifespan
of the system is up. Turning it off tends to wear out the battery
faster. Thermal shock is not much of a consideration though, if we
concede it will not damage equipment signficantl within its viable
lifespan which seems to be the case with all but the rare instances of
manufacturing solder pad defects or in-chip solder bump defects as seen
with certain chipsets in recent history.

Thanks for the great insights. Now I'm leaning towards turning off power
supply completely again!

 

[Nicholas Dreyer]

Up to you, but personally I never turn equipment off at the wall and
don't have any problem with doing so. It uses a single-digit # of watts
per system but the last power surge fault I saw was with a printer I
leave on because it's a networked printer that is inconvenient to go
turn off when it would be accessed by any random system on-site.

Before that it was a network switch which also never gets turned off for
similar reasons, a surge when through it and fried a port on it and a
network adapter in a client system.

Also in past years I'd found that some systems require a power reset if
they come back on from power off, rather than leaving mains on all the
time, so to me the chance of failure is lower than I deem the risk of
leaving power connected.

Well, this makes sense too. It sure is more convenient not to have to
reach around and fiddle with switches every time you boot up and down.
And I too have: (1) A flat screen monitor whose instructions
specifically say not to use the toggle switch too frequently, (2) An HP
laserjet that doesn't even have a switch, (3) a DSL modem and (4) a
router, all of which are on all the time.

I guess the switch will stay on for now!