Q: General Computer Watt Usage @ Low to Full Tilt

Soniclight wrote on 12/14/2007, 8:17 PM
For this Q, let's define:

--- low tilt as playing a compressed .wmv or .wma file with nothing else running or downloading some big file as I putter around cleaning up my room, monitors off (in my case, I have 2 LCDs that use up about 40 W each).

--- full tilt as VP8 or whatever other application in which CPU is at maximum and RAM is also copiously but not overworked, monitors on.

As my sys specs stated, I have a stand alone dual Pentium D system -- with 500 W power supply.

Point/Q: Does a computer munch up the same or relatively same amount of wattage whether in full or low tilt overall, or does it "self-regulate" it's appetite?

Comments

farss wrote on 12/14/2007, 9:20 PM
The harder they work the more power the use.
At full tilt power consumption can be many times what it is at idle.
Simplest way to guage this is to feel the heat coming out.

Bob.
riredale wrote on 12/14/2007, 9:35 PM
There are lots of power consumption articles around. Here is but one example. I'd say, very roughly, a PC eats about 100w at idle and 200w running video encoding. Add 50-100w for the LCD monitor.
GlennChan wrote on 12/14/2007, 9:39 PM
silentpcreview.com has some figures.

A high-end gaming machine with a video card draws something like 225W (the video card can draw a lot of watts).

2- Unfortunately, some PSU manufacturers fudge the specs of their PSU. The cheap 250W power supplies usually cannot deliver 250W at once.

Weight and price correlate with the actual performance of the PSU.

3- QT stands for quicktime... OT stands for off-topic. I hope that helps.
Coursedesign wrote on 12/14/2007, 10:52 PM
What does QT exactly stand for?

Sorry, that's on the QT.

:O]
Soniclight wrote on 12/15/2007, 6:38 AM
OK, thanks for replies. I suppose I'm just puzzled due to power supplies rating at 400 W on up these days on how that relates to actual power consumption. I assumed that my 500 Watt power supply meant that the computer used up to that amount of juice.

As to "QT" term used here, yup, I've been misreading all along: Ti's and O not a Q. Probably wouldn't have noticed the difference until now since my eyes got them thar plastic implants (cataracts fixed) - lol.
Kennymusicman wrote on 12/15/2007, 8:06 AM
Na - the PSU rating is meant to be a guide to how much power they can provide to the system, not how much juice they use at the socket.

As mentioned, it varies on many factors. Processor utilisation (different processors use different power - hence why intel core2 range is so good). How many bits you have in your system - more harddrives = more power required. Graphics card - as mentioned a big gaming card can require lots of juice just for itself and so on.

The only way to know what your system uses at load and idle, is to measure it at the plug.
Tinle wrote on 12/15/2007, 8:39 AM
At least some of the APC brand UPS battery backup systems come with a built-in software to monitor the power being provided to the computer

A Pentium P4, with 4 hard disks, moderate video card, and two monitors is running 220 - 250 watts as I type this.
Soniclight wrote on 12/15/2007, 1:10 PM
"A Pentium P4, with 4 hard disks, moderate video card, and two monitors is running 220 - 250 watts as I type this."

Sounds like a good ballpark I could apply since my system is similar-ish -- Pentium D, 3 internal SATA, one external Firewire IDE and a nVidia 6600XT with 2 LCDs -- those probably add up to about the same at socket.
John_Cline wrote on 12/15/2007, 3:05 PM
My quad core with 7 drives, an 8800 nVidia video card plus 2 Dell 2407 LCD monitors draws 432 watts at idle according to my APC UPS software. I guess I should start up a full render and see what it draws.

You could buy something like this device and measure the power consumption of everything you own:

http://www.newegg.com/Product/Product.aspx?Item=N82E16882715005

I own another product which is essentially identical to the Kill-a-Watt device at Newegg, it's called the "Power Angel" and is made by Seasonic. It's really pretty handy.
Soniclight wrote on 12/15/2007, 7:11 PM
Nice little gadgets, but I'm pretty strapped for cash now. Maybe wun of deez dazes...
Sol M. wrote on 12/16/2007, 11:28 AM
I have the Kill-A-Watt. Great little device to have around the house to analyze how much electricity things suck up.

How much power your computer uses can vary based on how many things you've got chugging along in it (hard drives, etc.)

But here's the readings I just measured:

System:
Intel E6300 (L2 Stepping - supposedly lower power usage) @ 2.9GHz
Seagate 320GB SATA HD
NVidia 7900GS Video Card

Idle/Low use (i.e. while typing this post): ~172W
Load (i.e 100% CPU use): ~215W (25% increase over idle)

To test the computer at load, I used Orthos, a stability testing program that makes both cores on my dual-core processor operate at full load (100%). This program really works the CPU, and not so much the other components (such as a hard drive, which would come into play when rendering in Vegas), so this is only an example of the difference in power use when the computer is at idle and full load.

BTW, while the Kill-A-Watt is a great device, I would not pay the $40 Newegg is asking, simply because you can easily find it for ~$20 at many places around the net.

Amazon for instance ($20.98):
http://www.amazon.com/P3-International-Kill-Electricity-Monitor/dp/B00009MDBU
John_Cline wrote on 12/17/2007, 1:57 PM
I had a full-up render going in Vegas with the all four cores pegged at close to 100% so I decided to have a look at the power consumption. At Idle my system draws 432 watts, when rendering it draws 501 watts.
Soniclight wrote on 12/18/2007, 12:17 AM
"My quad core with 7 drives, an 8800 nVidia video card plus 2 Dell 2407 LCD monitors..."

Nice system specs. Be it your your idle or full tilt figures, it looks like the number of hard drives seem to be where the wattage starts to add up.

I have 3 internal but only fire up the third when I need it (backup drive for my music production stuff in Cubase SX and such -- and one partition has my ready-to-go OS in case of boo-boos).
john-beale wrote on 12/18/2007, 11:40 AM
I use the Watts Up Pro (more expensive than you need for casual use).

My external 500 GB USB2 drives use around 10 watts each. Having externals is nice to carry between PCs, and turn them off when not used. I'm still using an old-school CRT which is well over 100 W.

It's interesting to see how power-inefficient a typical desktop design is, when you compare a laptop with similar specs, and then measure total power usage of each.

For typical Vegas tasks, my P4 2.8G desktop is sometimes a bit slower and sometimes a bit faster than my Dell Inspiron 9300 laptop, but it's certainly in the same speed ballpark. Including CRT monitor, the desktop runs around 250 W and the laptop runs about 35 W. Newer CPUs get better efficiency due to smaller device geometry but the CPU alone is just a fraction of the total, I think every single subsystem in the laptop does better power-wise.