Even 500W ain't enough for SLI.

CougTek

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[url=http://www.extremetech.com/article2/0 said:
ExtremeTech[/url]]
According to Jacobs, AMD had started seeing similar shutdowns with high-end, dual-graphics card setups recently. He was concerned that readers might attribute the problem to the power draw of the FX-60, which would be an incorrect conclusion. Jacobs pointed the finger squarely at dual-graphics cards, noting that the 512MB 7800 GTX can draw in excess of 11 amps when running full bore. If the two cards share a power supply rail, that means that more than 20A is being pulled from one power supply rail, which is a recipe for disaster. According to another source, AMD has started recommending 700W power supplies with high-end SLI or CrossFire setups to alleviate potential problems.

The issue, by the way, has nothing to do with the CPU. AMD was seeing these problems with CPUs as low as the single core Athlon 64 3200+, which draws relatively little power.
A computer that needs a 700W PSU is excessive, unless it's a mainframe or such. SLI and Crossfire shouldn't exist.
 

mubs

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I find the situation very amusing. In the data centers, they're screaming about power and air conditioning bills, and manufacturers are trying to address those concerns. In the PC market, current draw and heat are escalating!
 

ddrueding

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CougTek said:
SLI and Crossfire shouldn't exist.

What a stupid thing to say.

It's like saying the Concorde shouldn't exist, or that the Ferrari Enzo or Ford GT shouldn't exist. Exuberance and selective waste are the spice of life!

SLI and Crossfire are great! They just shouldn't be used for E-mail and word processing.
 

CougTek

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ddrueding said:
It's like saying the Concorde shouldn't exist, or that the Ferrari Enzo or Ford GT shouldn't exist. Exuberance and selective waste are the spice of life!
Well your three spices of life all consume exagerated fuel amounts and they all are very unefficient means of transportation. You can have "spice" and efficiency combined. Or at less reasonable efficiency. A Z06 Corvette consumes barely more than a regular mid-size sedan and I'm sure I could have you make it in your pants if I were the driver and you the passenger.
 

Santilli

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Sure, by David drives a VW, I think, and, I see no absurd waste in his life, just the reverse.

GS
 

Santilli

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Great post. Since my new box has a 500 watt Seasonic, maybe I better look at a 700 watt seasonic...
gs
 

ddrueding

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Even a hint of efficiency is not only not needed but is often unwelcome in matters of fun. I drive a VW that gets nearly 40mpg because I do 30,000+ miles a year. If I had a 10-mile commute to the office, you bet I'd have a 4+ Liter V-8 in a stomping beast, and would be most upset if they traded 50hp for 5mpg.
 

Santilli

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On the way to Davids house, I saw a Ford GT 40....

REALLY IMPRESSIVE, AWESOME!!!!!

S
 

CougTek

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I doubt these upcoming thermaltake PSUs will be as good as Seasonic's, but they have active PFC and hopefully their efficiency will be at least between 75%. That should add another quality product on the market. More choice is better.

Thanks for the heads up.
 

P5-133XL

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Or simply for $197+: PC Power and Cooling 510 SLI with 38A on the 12V rail
For those that need overkill and have price insensative budgets of $449+: PC Power and cooling 850 with 54A on the three seperate 12V rails.
For those that have unlimited ($489+) budgets: PC Power and Cooling 1KW with 66A on three seperate 12V rails.

See, if you need it, they will build it. All you have to do is pay, and pay, and pay.
 

Gilbo

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The big problem seems not to be wattage per se, but the current limiters mandated by ATX12V 2.0+ on the 12V rails.

It's not that the PSU's can't supply enough power, but that many PSUs won't allow that much power to go over any given rail for safety :roll: reasons. If you're building a system with large power requirements you should actively avoid PSUs with seperate rails. There's only one 12V regulator supplying them all anyway. The rails are individually limited to 20 amps, artificially. This creates all sorts of power supply problems in modern systems where certain components draw large amounts of power predominantly from the 12V line.

Irritating eh? Turns out that non-compliant spec PSU are actually better choices.
 

sechs

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In my experience, I can't say that this limitation has imposed any kind of limit. Then again, I use quality power supplies.
 
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