PC power consumption figures

[Trevor Wilson]

Some time ago, a poster wrote about using a 500 Watt power supply in a PC,
wrongly assuming that is how much power was consumed all the time. I argued
that a typical PC left powered up in an office, would consume between 70 -
100 Watts. I finally got around to testing my workshop PC in actual use. I
made no modifications to the machine. I left all the cards and drives
plugged in.

The computer comprises:

Gigabyte GAP35DS3P motherboard
Intel Core 2 Duo 6420 2.13GHz
2GB RAM
Main video card - NVIDIA GeForce 8500GT
Secondary video card - NVIDIA GeForce 8500GT
1 X 1TB SATA hard disk
3 X 500GB SATA hard disk
1 X Floppy drive
2 X DVD/CD burners
1 X Sound Blaster
1 X TV tuner card
1 X 350 Watt power supply
1 X Case fan (120mm)

Here are the figures I measured:

* Computer off (soft switch off) - 6 Watts
* Monitor off (soft switch off) - 4 Watts (Very ancient Sony 17" LCD -
analogue input only)
* Computer operating (web browsing, spreadsheet, et al - hard disks are NOT
asleep) - 139 Watts. When the hard drives power down, that figure will fall
to below 100 Watts.
* Monitor operating - 33 Watts

I am confident that more modern computers and those using on-board video, on
board sound, no TV card and one hard disk will consume considerably less
energy. Standby power figures for monitors would be lower, I expect. Typical
hard disks use more than 10 Watts each, so just using one hard disk will
reduce consumption by more than 30 Watts. In fact, that is precisely what I
intend doing. I will use USB connected drives, as an when I need extra
space.

 

[Mr.T]

Some time ago, a poster wrote about using a 500 Watt power supply in a PC,
wrongly assuming that is how much power was consumed all the time. I argued
that a typical PC left powered up in an office, would consume between 70 -
100 Watts. I finally got around to testing my workshop PC in actual use. I
made no modifications to the machine. I left all the cards and drives
plugged in.

The computer comprises:

Gigabyte GAP35DS3P motherboard
Intel Core 2 Duo 6420 2.13GHz
2GB RAM
Main video card - NVIDIA GeForce 8500GT
Secondary video card - NVIDIA GeForce 8500GT
1 X 1TB SATA hard disk
3 X 500GB SATA hard disk
1 X Floppy drive
2 X DVD/CD burners
1 X Sound Blaster
1 X TV tuner card
1 X 350 Watt power supply
1 X Case fan (120mm)

Here are the figures I measured:

* Computer off (soft switch off) - 6 Watts
* Monitor off (soft switch off) - 4 Watts (Very ancient Sony 17" LCD -
analogue input only)
* Computer operating (web browsing, spreadsheet, et al - hard disks are NOT
asleep) - 139 Watts. When the hard drives power down, that figure will fall
to below 100 Watts.
* Monitor operating - 33 Watts

Glad to see you finally proved to yourself that 172 watts when computer and
monitor are operating IS actually more than 70 - 100W then.

MrT.

 

[Trevor Wilson]

Glad to see you finally proved to yourself that 172 watts when
computer and monitor are operating IS actually more than 70 - 100W
then.

**Oh come on! Let's examine the reality:

* We were discussing typical OFFICE computers that were left powered
overnight and not actually doing anything.
* My computer uses two, relatively high consumption, video cards. Office
computers typically use on-board video.
* My computer uses FOUR hard drives and two DVD drives. Office computers
typically use ONE hard drive and one DVD drive.
* My computer uses a TV tuner card AND an audio card. Office computers
typically do not use a TV tuner nor an audio card.
* An office computer usually has the monitor and hard drives set to sleep
mode when not in use.
* The total consumption will be less than 100 Watts, if the office computer
is set up as one would normally expect. My Core 2 Due is several years old.
I expect modern chips would deliver far superior efficiency.

 

[RMD]

Hi All,

I've just checked what my computer is using (including the cable
modem).

Consumption = 60Watts

2.8Ghz Celeron, 4 hard drives, 2 DVD drives, 1 G of RAM, 4:3 LCD
display.

Ross

 

[Mickel]

* The total consumption will be less than 100 Watts, if the office computer
is set up as one would normally expect. My Core 2 Due is several years old.
I expect modern chips would deliver far superior efficiency.

I agree with everything you said except the bit about modern computers
using less power. The more modern the more power in my experience.

 

[Trevor Wilson]

I agree with everything you said except the bit about modern computers
using less power. The more modern the more power in my experience.

**Not so. The Core 2 Duo was spun out of work done by the Israeli section of
Intel, who were responsible for laptop chips. As you would be aware, laptop
power consumption figures have been steadily declining. Although they've
stuffed more transistors into the chips, sections of the CPU not being used
can be shut down, or reduced clock speeds used as required. It's pretty
clever stuff. Intel decided that the same power saving features could be
incorporated into desktop processors. Which is exactly what they have done
with the Core 2 Duo. Of course, the very highest performance CPUs will tend
to use more power, but the lower grade chips use considerably less. My Core
2 Duo uses far less power and runs much cooler than the Pentium IV (3GHz) it
replaced and it delivers considerably higher performance. I don't have first
hand experience of the very latest generation of chips, but I'll betcha they
use less power, not more. And of course, we are discussing CPUs not actually
doing very much here.

 

[Mr.T]

**Oh come on! Let's examine the reality:

* We were discussing typical OFFICE computers that were left powered
overnight and not actually doing anything.

Nope that was never part of your original claim.

* My computer uses two, relatively high consumption, video cards. Office
computers typically use on-board video.

And many don't, in fact many use more than one monitor! Many of course also
use higher power processors.

* My computer uses FOUR hard drives and two DVD drives. Office computers
typically use ONE hard drive and one DVD drive.

And how much power does your DVD drive actually use "at night when not doing
anything" Trevor? You really are clutching at straws!!!!!!!!!!!

* My computer uses a TV tuner card AND an audio card. Office computers
typically do not use a TV tuner nor an audio card.

And those would be some of the lowest users of power in any computer!
Try pulling them out and let us know if you get below that 100W "when the
computer is in use"?

* An office computer usually has the monitor and hard drives set to sleep
mode when not in use.

Your original claim was "when IN USE" !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Of course now it's "at night, when not in use". Shit mine draws exactly ZERO
under those conditions because it's *always* turned off at the mains at
night!

* The total consumption will be less than 100 Watts, if the office computer
is set up as one would normally expect.

Zero in fact at night when turned off. BIG DEAL!

My Core 2 Due is several years old.
I expect modern chips would deliver far superior efficiency.

Some do of course, but not by much over your relatively recent C2D, in fact
most of them draw FAR more than most computers did ten years ago. Hence the
far bigger heat sinks and far bigger power supplies that are now the norm.

Give it up Trevor, you cannot make your *original* claim accurate no matter
how you spin it!

MrT.