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SLI making PC shut down

Last response: in Graphics & Displays
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April 28, 2009 11:41:53 PM

My system is:

CPU: AMD Phenom II x4 940 3.00Ghz
RAM: PC2 6400 - 3GB
PSU: 700w ezcool
Motherboard: ASUS M3N-HD/HDMI
GPU: SLI Nvidia 9800GTX+

When I start the system up it works fine but when I went to update the Windows Vista index rating and it tried to test the GPU the system shuts down unexpectedly this also happens when I load a game up, what could cause this to happen?

More about : sli making shut

April 28, 2009 11:46:51 PM

Use something like SpeedFan to monitor your temps, the cards might be getting hot. And also I've never heard of ezcool, it might be the PSU. What are the amps on the 12V rail/
April 29, 2009 12:31:40 AM

This is most likely a case of the PSU not providing enough power to the Graphics Cards. Even though it is a 700W, it still sounds like that is the case.
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May 6, 2009 2:43:07 PM

Damn, I've got the same problem when I try and run mine in SLi, I've got an 800w EZcool, is the general consensus that it's a PSU problem then?
May 6, 2009 3:00:55 PM

Probably, EZCool sounds like a super generic, and they generaly are of rather poor quality. Find a nice 600-800W supply from PC Power and Cooling, Antec, Corsair, or OCZ.
May 6, 2009 5:06:20 PM

yeah it was for me i had to get a 1200 watt psu to keep it from moanin
May 7, 2009 12:38:03 AM

I'm having this same problem.

What i think I have it narrowed down to is that the 9800 GT 's have a max pull of 26A. My PSU has two 18A connections.

I'm about to order a new power supply, what I'm not sure of is that if the connections are single rail do I need a minimum rating of 52A to power the cards. Or would a rating over 26A be sufficent.
May 7, 2009 3:51:18 AM

Nvidia supplies this web site which will bring back a list of PSUs certified for your cards in SLI mode: http://www.slizone.com/object/slizone_build_psu.html .

If you want to get a PSU not on the list, you take on a little risk by figuring it out yourself and hoping you didn't miss something. You need enough amps added together to power two cards plus the rest of your system. If your card's docs say exactly how much watts and amps it draws, it's easy -- just double plus add the amount for the rest of your system. If they explain the total needed for system + 1 GPU, you can double it but then you need to figure out how much of that was for the system and subtract it out so it isn't counted twice.

Example, I have 2x 8800 GTS 512 SLI with a PSU that is 650W and 22A + 24A on the two rails. The GPU manufacturer recommends 425W 28A for one card. If I double that, I get 850W 56A ... that is more than my system has yet I know my system's OK. So being conservative I can subtract that difference and guess that's what my system needs in any future calculation ... which is 200W 10A.

So for instance if I was building 2x GTX 260 SLI which needs 525W 38A for one card, I can double that and subtract 200W 10A and figure that is what my system will need with the two new cards ... that is, I need to shop for an 850W 66A PSU solution.

Of course there's some uncertainty there, and I might lose some money or blow a component if I'm not careful ... but that's part of the fun for me.

Or you can use a PSU manufacturer's web site -- many of them have PSU calculators; ThermalTake's is pretty detailed: http://www.thermaltake.outervision.com/

Its results always seem low to me, but there it is.

Good luck.
May 7, 2009 5:03:50 AM

ssalesky said:
I'm having this same problem.

What i think I have it narrowed down to is that the 9800 GT 's have a max pull of 26A. My PSU has two 18A connections.

I'm about to order a new power supply, what I'm not sure of is that if the connections are single rail do I need a minimum rating of 52A to power the cards. Or would a rating over 26A be sufficent.



Tom's did an article on power consumption, and it turns out your 9800 GTs (aka 8800 GTs) consume about 10 amps each at max load. That's all. Card manufacturers grossly over exaggerate the requirements :ange: 


Nevertheless, your PSU still sounds like it's the culprit. Not because it's too weak though, but because it's just flat out not working right. Inconsistent power (such as power dips/spikes) can cause crashes in the same way that a weak PSU can. A new, high quality PSU would probably solve your issues, but you don't explicitly need a much stronger one.

Though it might be a good idea to get something stronger if you plan future upgrades ;) 
May 7, 2009 2:50:00 PM

Wow! thanks for the replys!

I had been looking at a Corsair TX750... and everything here and on the Nvidia site seems to support it as a good choice!

May 8, 2009 7:42:40 PM

@efeat, thanks for reminding us about the Tom's article on real-world power consumption. I had forgotten all about it.
May 8, 2009 8:02:55 PM

CeruLucifus said:
@efeat, thanks for reminding us about the Tom's article on real-world power consumption. I had forgotten all about it.


You're welcome. You'd be surprised how often it comes in handy...at any given time there's 2-3 threads asking if a PSU can handle something.
May 18, 2009 3:07:37 PM

Just an Update!

Thank You all for the replies!

Installed the PSU over the weekend, Corsair TX750, and have been running great!

No problems at all!
May 18, 2009 3:44:35 PM

Glad to hear it. Happy gaming!
!