Ars technica seems to be pretty legit....

[jdoggg12]

Power requirements have always been important. PCI-Express throws another power connector into the mix for video cards, further complicating things. While continuous power draw never exceeds more than 250W for the vast majority of high-powered gaming rigs, the God Box is quite a bit more demanding than most systems will ever be.

Since it has to handle two high-end video cards, two processors, and four, five, six, or even more hard drives, the God Box is one of the few configurations loaded enough to justify 600 watts or more. The Seasonic M12-600, Seasonic M12-700, and Silverstone Zeus 750W are probably among the most quiet units suitable. Zippy/Emacs, Delta, and NMB have even higher-end offerings, but then we start to leave the realm of workstation power supplies and head rapidly into redundant server-grade units. For the God Box, PCP&C is a safe, high-quality recommendation.

http://arstechnica.com/guides/buyer/guide-200703.ars/4

Is this true?

From this article, I would venture that ~ 500 watts would be all that all but the most massive systems need to run. My extrapolation is that 250watts would be the RMS power, and peakpower being somewhat less than double the RMS levels.

Wouldn't your typical high end cpu, 2 cd burners, 2 HDs, one or 2 8800gtx, 4-5 fans, etc would be more than fine with 500 or less watts by a good psu...

why do i see so many posts saying "ooooh with that setup you'll need 600, 700+ watts!" when the system they're talking about is less beefy than my example and considerably less than the god box?

 

[A5]

That sounds about right - unless you're running an insane SLI/Crossfire rig, you'll be just fine with a 400-450W PSU, and in most cases even lower if it's a particularly efficient unit.

 

[Lonyo]

A64 3200+/7800GT/2GB RAM/5 HDD's/1 optical/7 fans draws about 140w idle, and IIRC 200w max under load (gaming) from my personal experience.

I know it's not high powered, but add a dual core processor with similar TDP (which most have I believe, at 65nm or EE at least). Add in a faster graphics card, and you aren't going to jump a huge amount from 200W up to something stupidly high.
My measurements were also at the wall, meaning what the PSU draws, ignoring efficiency, so actual use will more likely be even less (since the PSU has less than 100% efficiency).

I have said this many times before in here.

Anandtech's own articles with top end overall systems and a graphics card such as an 8800 uses under 300w under max load (presumably at the wall, although I don't know for sure)

 

[DaveSimmons]

They are correct, also see total power draw notes in recent Video section reviews here at AnandTech.

The main reason people need to buy 400+ total watt PSUs is because most lower-watt PSUs lack enough amps on the 12v lines, if not for that a 300-350 watt PSU would be fine even for gaming rigs.

 

[nineball9]

My extrapolation is that 250watts would be the RMS power, and peakpower being somewhat less than double the RMS levels

The output of a power supply is DC which is not an alternating or variable waveform. Hence, RMS has no meaning in DC.

 

[jdoggg12]

i meant RMS as i use it to apply to car audio - which is to say, the continual average output. I don't know the term for DC current.

More like this
http://www.analytictech.com/mb313/rootmean.htm

Than the AC formula.



In the end, my intent was average continuous draw

 

[Captante]

Sounds pretty accurate to me as well ... my main gaming PC is similar in power draw to the "God-box" (minus one 8800GTX) & ran stable on a PC Power & cooling 510watt PSU 20-pin model ... even so when I upgraded to my current Seasonic M12-700, power draw from the wall actually dropped slightly so there is somthing to be said for buying more power then you actually need.

 

[Zepper]

I've hooked my Kill A Watt to my processor box and it never draws more than 200W from the wall so it actually requires about 150W from the PSU allowing for efficiency of 75%. I've recently been running it on my old Sparkle FSP250-60ATX. It ran a bit warm (the 80mm PSU exhaust fan occasionally steps up into the audible range) but the system is stable as a rock. If the sparkle had the proportion tipped more toward the +12 rail I wouldn't need another. I'm sure it is the +12 section that is getting warm so the fan has to ramp up. So I had to get a newer design just to keep the fan in slow mode.

.bh.

 

[Agentbolt]

The main reason people need to buy 400+ total watt PSUs is because most lower-watt PSUs lack enough amps on the 12v lines, if not for that a 300-350 watt PSU would be fine even for gaming rigs

He speaks the truth. I'd say for your average gaming rig, the amount of amps on teh 12V rail(s) is way more important than the wattage. The higher wattage ratings seem to be mostly a marketing scheme.

 

[Moose1309]

Article is correct. It's funny - I just plugged in my Kill-a-watt for kicks. Here's the rig I tested:

A64 4000+ at 2.94 and 1.4v
1 GB PC3200, 2.5v
X1800 XT, overvolted and clocked at 700/800
Maxtor 300GB SATA, Maxtor 160GB PATA
Seasonic S12-500 (overkill for my rig, I know)

Idle: 140W - 109w DC estimated
CPU Load: 175w, 138w DC est.
3DM06: 260w, 208w DC est.

This rig formerly had a dual-core (Opty 165 @ 2.5) and 2 GB, and it had similar draw numbers, except the CPU load was around 200 (wall AC) when dual-priming.

Pay no attention to the massive misinformation about PSU's. And - there are only about 3 brands I would buy.

 

[Moose1309]

Originally posted by: Captante
Sounds pretty accurate to me as well ... my main gaming PC is similar in power draw to the "God-box" (minus one 8800GTX) & ran stable on a PC Power & cooling 510watt PSU 20-pin model ... even so when I upgraded to my current Seasonic M12-700, power draw from the wall actually dropped slightly so there is somthing to be said for buying more power then you actually need.

The fact that the Seasonic was running more efficiently had nothing to do with the higher rating - but rather with the fact that Seasonics tend to provide higher efficiency even when they're running at lower capacity... If you went for the 500 or 600 watt model, I'd anticipate you'd get slightly higher efficiency than you have now.

 

[jdoggg12]

I think i'm going to put this thread in my sig for people too see every time someone says they need a 700+ watt PSU b/c that new 8800GTX-Utra-ZOMG vid card is a beast.

 

[Chaotic42]

Remember when Anandtech used to do these?

 

[Lonyo]

Originally posted by: Chaotic42
Remember when Anandtech used to do these?

Yeah, I remember 2 days ago. Do you?

 

[avi85]

Originally posted by: Lonyo

Originally posted by: Chaotic42
Remember when Anandtech used to do these?

Yeah, I remember 2 days ago. Do you?

LOL!

 

[Captante]

Originally posted by: Moose1309

Originally posted by: Captante
Sounds pretty accurate to me as well ... my main gaming PC is similar in power draw to the "God-box" (minus one 8800GTX) & ran stable on a PC Power & cooling 510watt PSU 20-pin model ... even so when I upgraded to my current Seasonic M12-700, power draw from the wall actually dropped slightly so there is somthing to be said for buying more power then you actually need.

The fact that the Seasonic was running more efficiently had nothing to do with the higher rating - but rather with the fact that Seasonics tend to provide higher efficiency even when they're running at lower capacity... If you went for the 500 or 600 watt model, I'd anticipate you'd get slightly higher efficiency than you have now.

Most likely correct ... the Seasonic is rated at 85% efficiency as I recall, although the 510 watt PC Power & cooling is pretty good too.

 

[Chaotic42]

Originally posted by: Lonyo

Originally posted by: Chaotic42
Remember when Anandtech used to do these?

Yeah, I remember 2 days ago. Do you?

Holy crap! It's not a dream system, but it's better than nothing.

 

[Moose1309]

Originally posted by: Captante

Originally posted by: Moose1309

Originally posted by: Captante
Sounds pretty accurate to me as well ... my main gaming PC is similar in power draw to the "God-box" (minus one 8800GTX) & ran stable on a PC Power & cooling 510watt PSU 20-pin model ... even so when I upgraded to my current Seasonic M12-700, power draw from the wall actually dropped slightly so there is somthing to be said for buying more power then you actually need.

The fact that the Seasonic was running more efficiently had nothing to do with the higher rating - but rather with the fact that Seasonics tend to provide higher efficiency even when they're running at lower capacity... If you went for the 500 or 600 watt model, I'd anticipate you'd get slightly higher efficiency than you have now.

Most likely correct ... the Seasonic is rated at 85% efficiency as I recall, although the 510 watt PC Power & cooling is pretty good too.

Yeah... the PC P&C are awesome, the Silencer 750 and the Seasonic S12 are pretty much tied in my book. I especially like the fact that PC P&C units are single-12v-rail.

EDIT best article I've found on PSU's is here. I'll be putting this in my sig, since I'm telling people to read it all the time anyway.
http://www.silentpcreview.com/article28-page1.html

I especially like the title of the sidebar on page 3: "POWER SHMOWER: or How PSU Power Ratings Mean Almost Nothing"

 

[herbiehancock]

Here's an interesting setup that's guaranteed to pull more than 700W from the wall:

Yeou Chin YCC-61F1 (aka Ultra M988 aka Globalwin YCC-61F1 aka Akasa Eclipse-62)
Asus L1N64-SLI motherboard
Two FX74 CPU's
Two Ultra X-Wind Copper 90MM CPU coolers
4GB DDR2-1000 (4 x 1GB sticks) Micro chips w/ Ultra copper heatspreaders
Two eVGA 8800GTX 768MB video cards
Two Seagate Barracuda 7200.10 750GB drives
BenQ DVD640 drive
X3 1000W PSU
Front and rear Ultra BB 120MM fans


It actually pulled, momentarily, over 1000W from the wall socket............

Provided some links to pics of what is being drawn from the wall as well as the cpu temps and ps temps........
The Weibo shows how much wattage is being pulled from the wall. The yellow type-K thermometer is the one that shows the CPU temperature as measured from the embedded thermistor. The thermometer in the lower right corner is a type-k and is measuring the air coming out of the PSU. Ambient air is 24C.

That's the max that was caught........998W from the wall socket....the 1KW draw was momentary and escaped being photographed.



http://www.jonnyguru.com/forums/attachment.php?attachmentid=500&d=1177549413



So, sometimes you DO need more than 700W power supplies......but not everyone does, this is true.

 

[magreen]

My electric water kettle uses 2000W.

 

[avi85]

Originally posted by: magreen
My electric water kettle uses 2000W.

your point being?
your computer doesn't have a heating element...(unless you have a prescott )

 

[pradeep1]

I think the wattage marketing is similar to megahertz marketing - more is better. I used to think that any modern computer needs a 400 W PSU, but after checking around on this forum, even a pretty beefy C2D can run safely and easily on a good quality 300-350W PSU. My actual draw on my recent overclocked C2D build with 2 HDDs, 2 Video Cards, 2 DVD Drives, and a bunch of fans, etc. is only 120-175 Watts.