Power consumption

Papercut · 12th Dec 2006, 05:38 PM

So I discovered that my dad has one of those clamp meters that can measure AC current draw. Multiply that by the AC voltage value (~240V here) and voila, you get the number of watts drawn by your power supply

First off, my system specs:
AMD Opteron 146 @ 290x10, 1.4V x 104%
DFI nF4 Ultra-D, LDT 1.3V and chipset 1.6V
2x512MB OCZ Value VX @ 207MHz, 2.9V
HIS Radeon X1800GTO @ 16 pipes, 612/612, 1.2/2.004/2.004V
Chaintech AV-710
200GB Seagate 7200.9 SATAII
BenQ DW1640
Toshiba DVD-ROM
Various fans
PSU is an Enermax 535W Noisetaker II, runs at close to 80% efficiency as tested by SPCR.

Current draw when idle:
0.46-0.50A

D2OL (CPU 100% load):
~0.63A

Gaming:
0.82-0.83A

So the PSU draws around 200W when gaming, give or take. At 80% efficiency, this would mean about 160W of power going to the actual components.

I also wanted to test something else - whether CPU clock speed scaling affects the amount of power it draws when the Vcore remains unchanged. So I downclocked my CPU to 207x10MHz (to maintain the same RAM speed) at the same voltage and got the following reading when running D2OL:
0.54-0.57A
Quite a big difference; I didn't really expect that.

Hope you guys found this interesting

Chai · 12th Dec 2006, 05:44 PM

Wow. We wanted to get that clamp meter too...

Not surprising, but still good to learn about that.

Adrian Wong · 12th Dec 2006, 06:06 PM

Yeah, that's a really good way of measuring the power usage.

Whowalks · 12th Dec 2006, 07:02 PM

thats quite interesting particularly as my PC is a similar config
146 opti
DFI expert
7800gt
320hdd
120hdd
\antec 550w neo psu

zy · 12th Dec 2006, 08:21 PM

cool ... i'm curious bout my pc power compsumtion too

Gasjatt · 13th Dec 2006, 01:16 AM

200W only when gaming?! That's so low, considering that you have a 535W psu. I guess we really dont need a big psu huh?

Papercut · 13th Dec 2006, 11:37 AM

Well personally I got a good deal on this PSU 2 years ago; I knew that it was going to be more power than I would use but it was worth it

You still have to put a bit of thought into the PSU selection process though; a PSU rated for 500W that cannot provide enough amps on the 12V rail(s) is not very suitable for modern components.

Still, you make an interesting point

Adrian Wong · 13th Dec 2006, 11:49 AM

Yup, don't just rely on the total power output. That's a myth.

Be sure to check the 12V output.

Gasjatt · 13th Dec 2006, 02:35 PM

then what psu is recommended for a system running E6400, x1950pro, 1GB DDR2 and all the other usual stuff...??

ZuePhok · 13th Dec 2006, 04:03 PM

Quote:

Originally Posted by Gasjatt

then what psu is recommended for a system running E6400, x1950pro, 1GB DDR2 and all the other usual stuff...??

a reliable 450w PSU will do.

papercut: i must get one!

12th Dec 2006, 05:38 PM	#1 (permalink)
Papercut Hold me back! I can't stop posting!!! Join Date: 14 Jul 2004 Location: Singapore! Posts: 5,102 Reputation: 2557 Rep Power: 36	Power consumption So I discovered that my dad has one of those clamp meters that can measure AC current draw. Multiply that by the AC voltage value (~240V here) and voila, you get the number of watts drawn by your power supply First off, my system specs: AMD Opteron 146 @ 290x10, 1.4V x 104% DFI nF4 Ultra-D, LDT 1.3V and chipset 1.6V 2x512MB OCZ Value VX @ 207MHz, 2.9V HIS Radeon X1800GTO @ 16 pipes, 612/612, 1.2/2.004/2.004V Chaintech AV-710 200GB Seagate 7200.9 SATAII BenQ DW1640 Toshiba DVD-ROM Various fans PSU is an Enermax 535W Noisetaker II, runs at close to 80% efficiency as tested by SPCR. Current draw when idle: 0.46-0.50A D2OL (CPU 100% load): ~0.63A Gaming: 0.82-0.83A So the PSU draws around 200W when gaming, give or take. At 80% efficiency, this would mean about 160W of power going to the actual components. I also wanted to test something else - whether CPU clock speed scaling affects the amount of power it draws when the Vcore remains unchanged. So I downclocked my CPU to 207x10MHz (to maintain the same RAM speed) at the same voltage and got the following reading when running D2OL: 0.54-0.57A Quite a big difference; I didn't really expect that. Hope you guys found this interesting __________________ "Use in a cool dry place away from direct sunlight. Keep out of reach of n00bs. Overclock within 24 hours of opening. Do not read instructions before proceeding, do not use only as directed. May cause frustration, late nights and empty wallets. If symptoms persist please consult your hardware professional."

12th Dec 2006, 05:44 PM	#2 (permalink)
Chai Administrator Join Date: 6 Oct 2002 Location: Maranello Posts: 27,870 Reputation: 4630 Rep Power: 81	Wow. We wanted to get that clamp meter too... Not surprising, but still good to learn about that. __________________ Chai (Contributor & Forum Admin) http://www.techarp.com/

12th Dec 2006, 06:06 PM	#3 (permalink)
Adrian Wong Da Boss Join Date: 10 Oct 2002 Location: In front of my ASUS F8V notebook! Posts: 32,208 Reputation: 3531 Rep Power: 75	Yeah, that's a really good way of measuring the power usage. __________________ Dr. Adrian Wong Tech ARP \| Blog @ Tech ARP \| The Free Trade Zone DYKT : The only offshore account I have is at the sand bank? We need PROGRAMMERS and TECHNICAL WRITERS! Contact us if you are a hot shot programmer or technical writer! My items for sale : 50x SD Card \| Memory Stick PRO \| Cyclone Energy Saver \| Seiko SS watch \| Tiger/Carlsberg beer jugs \| Travel Speakers \| Motorola V600 \| Nokia N90 SOLD! \| New Lowepro Mini Trekker AW Other items for sale @ the FTZ : Zalman CNPS9500 LED @ $20 \| Zalman CNPS7700 Cu @ $20 \| Zalman CNPS7000 Cu @ $20 \| Swarovski bracelet watches \| Dell 17" LCD \| Hi-Fi speakers \| English DIVX movies \| HP LaserJet toners! \| Office chairs

12th Dec 2006, 08:21 PM	#5 (permalink)
zy Dead Join Date: 16 Dec 2002 Location: Buffalo NY / Penang MY Posts: 13,305 Reputation: 2158 Rep Power: 41	cool ... i'm curious bout my pc power compsumtion too __________________

13th Dec 2006, 11:37 AM	#7 (permalink)
Papercut Hold me back! I can't stop posting!!! Join Date: 14 Jul 2004 Location: Singapore! Posts: 5,102 Reputation: 2557 Rep Power: 36	Well personally I got a good deal on this PSU 2 years ago; I knew that it was going to be more power than I would use but it was worth it You still have to put a bit of thought into the PSU selection process though; a PSU rated for 500W that cannot provide enough amps on the 12V rail(s) is not very suitable for modern components. Still, you make an interesting point __________________ "Use in a cool dry place away from direct sunlight. Keep out of reach of n00bs. Overclock within 24 hours of opening. Do not read instructions before proceeding, do not use only as directed. May cause frustration, late nights and empty wallets. If symptoms persist please consult your hardware professional."

12th Dec 2006, 07:02 PM	#4 (permalink)
Whowalks Newbie Join Date: 2 Dec 2004 Location: Western Australia perth Posts: 23 Reputation: 0 Rep Power: 0	thats quite interesting particularly as my PC is a similar config 146 opti DFI expert 7800gt 320hdd 120hdd \antec 550w neo psu

13th Dec 2006, 01:16 AM	#6 (permalink)
Gasjatt Warming up Join Date: 10 Nov 2004 Location: Penang, M'sia Posts: 134 Reputation: 104 Rep Power: 6	200W only when gaming?! That's so low, considering that you have a 535W psu. I guess we really dont need a big psu huh?

13th Dec 2006, 11:49 AM	#8 (permalink)
Adrian Wong Da Boss Join Date: 10 Oct 2002 Location: In front of my ASUS F8V notebook! Posts: 32,208 Reputation: 3531 Rep Power: 75	Yup, don't just rely on the total power output. That's a myth. Be sure to check the 12V output. __________________ Dr. Adrian Wong Tech ARP \| Blog @ Tech ARP \| The Free Trade Zone DYKT : The only offshore account I have is at the sand bank? We need PROGRAMMERS and TECHNICAL WRITERS! Contact us if you are a hot shot programmer or technical writer! My items for sale : 50x SD Card \| Memory Stick PRO \| Cyclone Energy Saver \| Seiko SS watch \| Tiger/Carlsberg beer jugs \| Travel Speakers \| Motorola V600 \| Nokia N90 SOLD! \| New Lowepro Mini Trekker AW Other items for sale @ the FTZ : Zalman CNPS9500 LED @ $20 \| Zalman CNPS7700 Cu @ $20 \| Zalman CNPS7000 Cu @ $20 \| Swarovski bracelet watches \| Dell 17" LCD \| Hi-Fi speakers \| English DIVX movies \| HP LaserJet toners! \| Office chairs

13th Dec 2006, 02:35 PM	#9 (permalink)
Gasjatt Warming up Join Date: 10 Nov 2004 Location: Penang, M'sia Posts: 134 Reputation: 104 Rep Power: 6	then what psu is recommended for a system running E6400, x1950pro, 1GB DDR2 and all the other usual stuff...??

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Taking Power Naps!	aKho	Lounge	29	21st Feb 2007 10:03 AM
Calculating Power Consumption	noodle	General Hardware	7	10th Jun 2006 09:10 AM
New VIA Technology Innovation Center in Mumbai to Develop Power Saving PHD Computing	Dashken	News	0	27th Jan 2006 09:24 AM