top end pc's.....power usage....suprising

james.miller · 31 May 2007 at 20:37

ok so i had the opportunity to play with a device use to measure current draw at the mains. i only had 10 minutes or so to play so nothing in depth (yet) but it was an interesting 10 minutes.

My specs are listed at the bottom of this post. now considering the device was plugged in between the wall socket and the 4-way strip that powers my pc, my 22" dell tft, my router and my modem, what do you guys think the gear is drawing from the mains whilst running superpi on one core and 3dmark on the other?

ill tell you in 30 minutes or so.

my specs:

e6600 @3.2ghz
2ghz ddrII
8800gtx @ stock
7300gt
xfi gamer
two 18x dvd writers
360 hd-dvd drive
two 500gb hdd's, one 250gb
imon ultrabay vfd
all-in-one card reader
corsair HX 620w psu

james.miller · 31 May 2007 at 21:15

ok well its been half an hour.. i was expecting more replies but maybe people are worried they'd get it wrong

anyway with the tester plugged in i booted up the pc and straight away we saw a 1.2amp load. 288watts, in other words. that's a fair amount considering it wasn't doing very much and did suprise me some what, but booting in to vista saw a 1.3amp peak (312watts) as the optical drives span up and it did its thing which wasnt a huge increase.

as I ran superpi on one core and 3dmark's nature tests on the other, the maximum peak was 1.6amps, 384 watts. that's it, thats all it could muster lol. This is only a short test but if nothing else it does prove that recommended ratings and 90% of what people will tell you you *need* on a hardware forum.....is complete tosh.

so what do you think then? and well done gt_junkie and Craig_kennedy83 for guessing virtually on the button

james.miller · 31 May 2007 at 21:20

i was running superpi AND 3dmark at the same time

james.miller · 31 May 2007 at 21:32

Jokester said:
Can you do it again, with only measuring the actual current used by the PC PSU?

Jokester

i will do. in the next couple of days, ill have the tester for a few hours and ill do some thorough testing on the pc itself

Tad OT: Why do you have a 7300gt as well?

I have (well, had) dual monitors. my 22" dell and a 19" acer that i recently sold. ill be getting either another 22" or a 24" to replace the acer. ive also got my 40" sony which is connected up. my 8800gtx is connected to my 22" and my sony, the 7300gt is for the 3rd monitor

james.miller · 31 May 2007 at 21:42

CS||nuTs said:
Was there any fluctuations,i mean major ones?

not as far as i could see. unfortunately the equipment didnt measure in watts so the best accuracy we had was to withing 0.1amps, 24watts basically. even given that, the total draw was still WELL below with would officially be recommended for the pc. given that the 384w (1.6amps, although in reality it could have been +/-12w of that figure) figure was for everything connected to that strip, its not unfiar to say the draw of the pc could have been closer to 360w or less.

james.miller · 31 May 2007 at 21:51

that's certainly possible i wouldnt have thought. also people with psu's that aren't as efficient would see a higher power draw - the corsairs are some of the the most efficient psu's you can buy.

james.miller · 31 May 2007 at 22:35

PhillyDee said:
Hehe, what about me . . . . Do i get a prize?

ha good try but no

james.miller · 31 May 2007 at 23:06

how is it flawed? i tested the entire draw from the wall socket. you can get much better than that. If you test after the psu then you aren't accounting for additional draw of the psu as it isnt 100% efficient. As you know, the psu is also part of the pc

james.miller · 31 May 2007 at 23:10

Jokester said:
Yeah, but it's including things not powered by the PC PSU, the monitor alone will use something of the order 60-80W.

Jokester

he isnt talking about that jokester, and i did say it was the draw of the entire setup. its not a flawed test as i tested exactly what i said i would

the only thing that you can say for sure is that *** draw of the pc alone would be even less, but that makes no difference to this test.

that IS also why i said i would test the pc separately in the next few days...

james.miller · 31 May 2007 at 23:12

what difference does that make?

james.miller · 31 May 2007 at 23:16

Jokester said:
Ahh I see what he means, if you want to work out the actual power used by the PC just multiply PSU power by it's efficiency, typically 70-80%, but it'll vary with power demand.

Jokester

thats right. according to JohnnyGuru the 620w corsair is roughly 82-83% efficient @ with a ~380w draw. for argument's sake, if that 384w load was the pc alone that would mean the components were actually drawing around 318 watts.

of course that isnt the case, and if the draw form the mains is closer to 350w, the draw of the components could be as low as 290w. Again i will test all of this very soon

james.miller · 31 May 2007 at 23:22

Millwall.FC said:
you said "as I ran superpi on one core and 3dmark's nature tests on the other, the maximum peak was 1.6amps, 384 watts. that's it, thats all it could muster lol. This is only a short test but if nothing else it does prove that recommended ratings and 90% of what people will tell you you *need* on a hardware forum.....is complete tosh"
but you only measured the draw of the psu not the actualy wattage the pc is using.

forgetting what else was plugged in, i measured what the psu was pulling from the wall socket. that IS what the pc is using. All the components, the inefficiency of the psu also...everything

james.miller · 1 Jun 2007 at 23:46

that was tested at 240v. there's no way it was near 90% efficiant, that would make it opne of the most efficient switch mode power supplies in the world lol