Can my PSU handle G80 SLI?

aka1nas

Diamond Member
Aug 30, 2001
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I am exploring my options for a GPU upgrade and was curious. The Neo550HE is not on the list for 8800 series SLI, but that may just be due to the age of the model. It's SLI certified for anything below the G80 and pretty much every Crossfire configuration. Would it be possible to run a pair of 8800GTSs on this PSU?
 

40sTheme

Golden Member
Sep 24, 2006
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Hmm, it's hard to tell. With the amount of OCing done on your rig, you may want to upgrade to a 650-700W PSU. I'd let some other people chime in with their views, however, before you spring on something. I dunno, I'd just feel uncomfortable with that wattage with those low latencies and the OC on your Opty. What's the amperage on that PSU?
 

aka1nas

Diamond Member
Aug 30, 2001
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IIRC, it's 18A on each of the three 12v rails and ~42A total for all three rails.
 

Matt2

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Jul 28, 2001
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my Fortron Blue Storm 500w wasnt SLI certified, but it ran my 7800GT SLi flawlessly.

I know its apples and oranges, but sometimes that SLi certified list can be over the top.
 

Gstanfor

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Oct 19, 1999
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Originally posted by: Matt2
my Fortron Blue Storm 500w wasnt SLI certified, but it ran my 7800GT SLi flawlessly.

I know its apples and oranges, but sometimes that SLi certified list can be over the top.

If you are going to spend the sort of money required for SLI'd 8800's why would you skimp or take chances on the PSU? Makes no sense to me unless you are penny-wise and pound-foolish.
 

aka1nas

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Aug 30, 2001
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As I mentioned above, it was SLI certified for anything below G80. It looks like they only will certify new/current PSU models with the newer cards. The newer 650 watt Antec model is SLI certified for 8800GTS SLI. Supposedly my PSU is certified to run a pair of 7900GTXs. Are the 8800GTS models much more power hungry?
 

aka1nas

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Aug 30, 2001
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Also, if it's helpful at all, I have used PowerChute personal edition with my UPS to monitor the power consumption of my rig when I was running XP. In games or with a 3dmark06+Orthos stress test, my load power consumption never goes much above 280 watts.
 

Gstanfor

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Oct 19, 1999
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Originally posted by: aka1nas
As I mentioned above, it was SLI certified for anything below G80. It looks like they only will certify new/current PSU models with the newer cards. The newer 650 watt Antec model is SLI certified for 8800GTS SLI. Supposedly my PSU is certified to run a pair of 7900GTXs. Are the 8800GTS models much more power hungry?

Its not certified for 7900 GTX either if you check.

Yes, g80 has significantly larger power draw than g71. Have you ever compared the two dies sizes, just for starters?
 

Viper GTS

Lifer
Oct 13, 1999
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I should probably go back and update my thread, but my issue was not power related.

So it's not really fair to use it as evidence, though I would completely support the opinion that a NeoHE 550 is not sufficient for G80 SLI.

Viper GTS
 

aka1nas

Diamond Member
Aug 30, 2001
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Originally posted by: Gstanfor
Originally posted by: aka1nas
As I mentioned above, it was SLI certified for anything below G80. It looks like they only will certify new/current PSU models with the newer cards. The newer 650 watt Antec model is SLI certified for 8800GTS SLI. Supposedly my PSU is certified to run a pair of 7900GTXs. Are the 8800GTS models much more power hungry?

Its not certified for 7900 GTX either if you check.

Yes, g80 has significantly larger power draw than g71. Have you ever compared the two dies sizes, just for starters?

Sorry about that, I misread the chart the first time around. :eek:
 

nZone

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Jan 29, 2007
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Maximum Power Draws for single: GTX = ~180w; GTS = ~150w. It might be doable if it is a GTS by having a PCI-E power on one of the card connects to the either 3.3v or 5v line (recommended by Antec). This guy has a GTX SLI on Corsair 620w PSU which has a maximum 50A on 12v rails. The NeoHE has 42A on 12 rails. Both of these PSU are manufactured by Seasonic and both PSUs have single 12v in the backend.

Here is the link: http://www.legitreviews.com/article/462/1/
 

Woofmeister

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Jul 18, 2004
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In my opinion, SLI certification is a marketing gimmick Nvidia dreamed up. We don't know what's involved in certification and whether an objective criteria is even involved. Originally, the only approved PSUs for the 800GTXs in SLI were those with 1000 watts. Recently, Nvidia has expanded the list to include some models that are rated as low as 750 watts. Quality of design means more than claimed wattage as the Corsair HL620's ability to power 800GTXs in SLI despite its modest 620 watt claimed output demonstrates.

If you check out my original post here, you'll see that the Inquirer was able to power an overclocked Core 2 Extreme QX6700, Nforce 680i, Dual 8800GTXs in SLI and water cooling with a 500 watt PSU.

All that being said, I would not count on a Neo550HE being able to drive dual 8800GTXs over the long haul. Moreover, since the Neo comes with only two PCI-Express cables, the PSU cannot power two 8800GTXs (which require two PCI-Express connectors each) without two splitter cables thereby further increasing resistance.
 

aka1nas

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Aug 30, 2001
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Yeah, I definately wouldn't try to run a pair of GTXs on this PSU. They won't fit in my case anyway.

Nor in my budget! :D
 

aka1nas

Diamond Member
Aug 30, 2001
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Hmm it looks like the Neo 550HE is certified for all X1900/X1950 Crossfire combinations. That's a good sign, right? According to this AT Review, The X1950XTX uses more power than an 8800GTS at full load.
 

conlan

Diamond Member
Jan 27, 2001
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Regardless of the nVidia chart i linked earlier, i don't see why a quality 550W PSU like yours wouldn't run 2 GTSs.
 

ss284

Diamond Member
Oct 9, 1999
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I'm pretty sure I've seen people with Neo 550s and two 8800GTS's listed in their sig. I would test it for you, but sadly I dont have two 8800s in my back pocket.
 

idiotekniQues

Platinum Member
Jan 4, 2007
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the corsair 620ex can run 8800gtx sli and it isnt on any of the lists for 8800gtx or gts.

i dont think the lists are the be all end all of what ps can handle it.
 

CP5670

Diamond Member
Jun 24, 2004
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Originally posted by: aka1nas
Hmm it looks like the Neo 550HE is certified for all X1900/X1950 Crossfire combinations. That's a good sign, right? According to this AT Review, The X1950XTX uses more power than an 8800GTS at full load.

Those cards use more than the GTXs too, in Crossfire mode. See this article. It will probably work fine.
 

nZone

Senior member
Jan 29, 2007
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This thread is about Antec 550 NeoHE and don't wish to still it. But this can provide some guidance. I have a 550 NeoHE too but was thinking of swapping out for a better wattage.

This is from Corsair directly (for Corsair 620w PSU):
=================================
In our internal testing, we've identified that at full load, an 8800GTX consumes around 160-170W of power from the +12V rail. This is about 14A.

Two of them total to 28A.

The rest of the hardware is dependent upon your configuration, but an Intel Quad-Core processor (QX6700) overclocked to 3.3 GHz on an eVGA 680i motherboard draws about 11A from the +12V rail. So now we're at 39A.

Add a couple hard drives at 1A each, you're between 40-45A on the +12V rail at your ambient case temperature (which is most frequently between 35C and 40C) and our HX620 can handle 50A on the +12V at 50C, even more down at 35C and 40C.

If you have some huge number of hard drives, like more than 6, you might want to look into a higher-wattage supply. Keep in mind, it's not running at those ratings at idle.

At idle, the G80 draws about 7A, or 84W of power. The processor draws 4A, or 48W of power. The same system above that draws ~45A at full load will probably draw less than 20A at idle.