Power factor, UPS, computer

[Tim Streater]

No domestic computer needs that much power.

[The Natural Philosopher]

can do in short bursts

if its got some gamers video GPU..

[Uncle Peter]

Games can be played for hours. And you can do processing on a video card (BOINC or Bitcoin for example). A good graphics card can be up to 375 watts. And of course you can install a couple of them.

[John Williamson]

You don't play games, then? That and video editing are the main consumer of domestic CPU and GPU cycles, and they both use a *lot*.

Shows up to 491 watts per card, and some gamers will insist on one card per diaplay....

[Uncle Peter]

I can tell you as I own one that those cards are shit. You can't keep them cool enough to run at full power. It's two 7970 chips on one card (with the same three fans, so totally inadequate cooling). Best thing to do is to get two rear exhausting cards (7970 and 7990 blow heat into the case, R9 290 is better).

[John Williamson]

I wasn't recommending it, just using it to point out that modern gamers' video cards use a lot of power.

The power used by this computer totals about 90 watts, including battery charging. The other one uses about half that. For office work, I have one that uses about 40 watts if I attach it to a reasonable LCD display, or about 10 if I use the built in screen, which to be fair, is almost as useless as a chocolate teapot.

[Uncle Peter]

My desktops idling use over 100W. Fuck knows where it's going. The graphics chip and CPU are both cold. Add 90W for each of the two LCD monitors.

I now have a UPS by the way. 1500VA (960W) Smart UPS (2nd hand), plus new batteries - not the right ones, but I rewired them. It's quite happy giving out enough power for the graphics card and CPU at max plus two monitors and the stereo. Plus it's got a USB link to the PC so I can see the battery level, and the PC can go to sleep or hibernate if the battery runs low, just like a laptop, except the battery is a little larger :-) It predicts 18 minutes runtime at full load (full PC load, not full UPS load), but I don't need more, if I did I could add car batteries. All I ever get here is little power dips that flicker the lights and shut the PC off in stormy weather. I think I've had one two hour powercut in 13 years.

[Andrew Gabriel]

Wanna bet!

[Uncle Peter]

I'm thinking of the bog standard office PC used for word processing. Dell Optiplex for example. 200W I believe.

[Bob Eager]

My home servers mostly use these:

although they only use about 30W....

[Bob Eager]

They don't use that - they don't use enough power.

And the GPU is onboard.

[Tim Streater]

Doubtless. But only a yo-yo would want to do that.

[Uncle Peter]

Then you're not doing anything very interesting.

[Uncle Peter]

Why would anyone play a game for a few minutes?

[John Rumm]

Games players rigs frequently need that and more. The more exotic gfx cards are rather thirsty when doing heavy rendering, and some of these rigs parallel up multiple cards.

[John Rumm]

Yup, that's handy, thanks.

[Tim Streater]

Non yo-yos have better things to do.

[Vir Campestris]

How sure are you that the majority of current is drawn on the 12V line?

Remember that others have quoted multi-hundred-watt GPUs...

Andy

[Uncle Peter]

They wouldn't play any games.

[Uncle Peter]

Because the GPU is connected to 12 volts by its own connectors. And the CPU has its own 12V connector too. Fans are also 12V. And disks are half 12V half 5V.