SLI and CrossFire Push Power Supplies to the Limit

5 Mar, 2006 at 10:38pm ET Article published in Tech

Extremetech explores why some highend PSUs are failing under the strain of highend SLI & Crossfire setups.

It turns out that Powersupply design is a big part of the problem. Fire up SLI/CrossFire system loaded with multiple drives, multi-Gigabytes of memory…no problems. BUT Benchmark a SLI/CrossFire system with just a single drive and Poof – system shutdown!

View: SLI and CrossFire Push Power Supplies to the Limit

This power supply is rated for 650 watts, and is SLI certified by Nvidia. So we fired up an Nforce4 SLI X16 system with two 512MB graphics 7800 GTX graphics cards and an Athlon 64 FX-60. About halfway through the 3DMark06 run, the system shut down. There was no warning, no smoke, no heat. It just turned off.

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

New configurations, New capabablities, New Problems.

Leading Edge is Bleeding Edge!

Source: ExtremeTech

Comments

6 Mar 2006 ~ 10:45am csimon I just read part of a review or article on a thermaltake dedicated gpu psu rated at 250w ...sounds like an excellent solution and it fits in a 5.25 bay.
6 Mar 2006 ~ 10:54am primesuspect omg i knew it would come to this. We were joking around about it when nvidia first started announcing the 6800 series, but..... a dedicated PSU for the video card(s).... wow...
6 Mar 2006 ~ 11:38am csimon

primesuspect wrote:

omg i knew it would come to this. We were joking around about it when nvidia first started announcing the 6800 series, but..... a dedicated PSU for the video card(s).... wow...

http://www.dailytech.com/article.aspx?newsid=1115
6 Mar 2006 ~ 4:13pm Leonardo

AMD has started recommending 700W power supplies with high-end SLI or CrossFire setups

And up to 20A on a voltage rail? Wow, in comparison, my dual core-power hungry-flame belching Intel D820 processors would appear to be very modest.
6 Mar 2006 ~ 5:14pm Omega65 FSP VGA Power Supply

So now each major component will have it's own PSU?
6 Mar 2006 ~ 6:45pm Looks to me the best idea would be to have the video cards plug into the wall via an adapter.. Dunno if it's viable but sounds better than having another item in the case.
7 Mar 2006 ~ 1:57pm Armo they used to do that with the voodoo5, lol