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SLI - Mainboard conflict? (9800GTX+)

Last response: in Graphics & Displays
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January 29, 2011 5:44:06 PM

Hi all,

this is the first time I'm using this platform actively, so please be gentle :-)

My computer consists of the following:

Gigabyte M57SLI-S4
AMD AM2 7750 DualCore
2x2GB noname RAM
CoolerMaster Real Power M700 PSU
Win7 x32
XFX 9800GTX+

Now I bought another XFX9800GTX+, used, but functional when I use it alone.

I put both cards in, provided the first (original) card with the two 6-pin-cables from the PSU (which has two dedicated slots for that), and bought two split-cables, that on one side have 6-pin connections and on the other have connections so I can plug them to the S-ATA power cables.

So both cards are provided with electricity, one through dedicated cables, the other through split-cables.

I connected the 2-way-SLI-bridge to the very left of both cards.


Now, what happens when I start the computer is mostly that power goes on, you hear the two card's fans charging up, then down, and nothing further happens. Every 15 secs or so the GPU fans spin up, down, and nothing more.

Sometimes then I can't even start my computer (same behaviour) when having taken out the 2nd GPU, which is when I use a jumper to reset the motherboard's BIOS.

Mostly then I can boot normally into Windows.

Sometimes, right after resetting the BIOS, when I put in the 2nd GPU card, the computer will boot up and loads into Windows, but the Nvidia software does not show any SLI options. Checking the device manager, there is only one card listed.

That happened only twice though, and the first time I thought that maybe my Nvidia software was outdated, so I downloaded the newest one, but the installation got stuck. Upon reboot, the same old problem came up - computer won't boot much.

I do think that both GPU's have the same BIOS version, having looked at that in GPU-Z.


Does anybody have any idea what I could do, what I've missed, or misunderstood, or fouled up? :-)

Thank you.
January 29, 2011 6:15:40 PM

What are the PSU specs?
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a b Î Nvidia
January 29, 2011 8:32:25 PM

The unit would have to be defective to not be able to supply enough power to the system so I doubt that it is the problem but keep it in mind. Try to test each card alone in that system even though they are known to be good but is to search out for issues. I am thinking that it is either the cabling or the board at this time.
January 29, 2011 9:16:51 PM

both cards work flawlessly when inserted alone.

Windows loads just fine, I can play TrackMania, World in Conflict, Starcraft 2, no probs.

Only when I have both in at the same time does my computer not boot up.



Also, I think I forgot to mention that the screen remains on standby when the computer doesn't boot.

I am thinking about flashing both GPU to a newer BIOS...
a b Î Nvidia
January 29, 2011 9:40:21 PM

I am doubtful that the bios is of any issue. I believe that it is your board or there is a power issue. If both cards work alone then it can't be a bios related issue on any of the cards nor the board. A bios issue would leave the cards not working at all on that bard but working on other boards with no issues.
January 29, 2011 11:53:40 PM

I think we are back to the PSU...Do you have another you can test with?
January 30, 2011 12:11:54 AM

unfortunately, no.

what I intended to do was ask in the near computershops to test both video cards for SLI function..

I don't have the money right now to buy extra components, so no chance to test with another mainboard or PSU..
January 30, 2011 1:03:11 AM

I just flashed both video cards independently, and now at least the computer is starting up fine.

still Windows doesn't show two video cards, and the Nvidia interface doesn't mention SLI anywhere..

had a freeze though 2 mins ago.. cross your fingers
January 30, 2011 10:14:59 AM

SLI is activated now.

I do get strange colorful flickering no matter in which direction or on which of the two possible SLI ports I install the SLI bridge.

Removing the bridge helps, but whenever I play a game, after a couple of minutes it will stop, the computer jumps to the desktop, then jumps into the respective game again, and on it goes.

Guess now it's only down to drivers...
January 30, 2011 10:20:38 AM

Actually, you could get those symptoms from an under powered PSU, one that puts out almost, but not quite enough power.
January 30, 2011 4:30:18 PM

Ok, I checked the power requirements of my setup on the following page:

http://www.coolermaster.outervision.com/PSUEngine

The result it gives me is that I should have a 500W-PSU for single-GPU-mode, and a 600W-PSU for SLI-mode. I own a 700W-PSU explicitly stating that it can do SLI.

Thus I tend to hope that my PSU is not the culprit.

I tried using different BIOS files from MVKTech, the problem I now have is that in some positions of the SLI bridge the games show flickering, and in some not, and when I remove the bridge, there's no flickering at all.

In all cases though the games tend to crash. I just got my first message from Windows saying that the driver crashed and then recovered...
a c 172 Î Nvidia
January 30, 2011 5:19:18 PM

It is possible that the bridge is faulty.
a b Î Nvidia
January 30, 2011 7:25:19 PM

The only way to make sure that the psu isn't at fault is to check the volts to see if they are low or to high and that they remain stable rather than having large changes over a short period of time.
January 31, 2011 4:30:25 AM

Alright.

I'll start looking for a new PSU .. 750W or more, just to see if my almost three year old PSU has a problem.

I don't suspect the SLI bridge atm, but I'll be sure to test my system with an alternative bridge once I have a new PSU.


Thank you guys, I'll let you know how it's going.
January 31, 2011 5:53:00 AM

I just opened a support ticket with Cooler Master, asking 1) if my PSU is sufficient for my setup, and 2) how to connect both video cards to the PSU exactly.


What I forgot to mention last night is that since I updated the GPU BIOS of both cards to 'XFX 98GTX+ Rev.02'
from MVKtech, the computer won't start up anymore when Windows wants to use its generic drivers, but starts normally with the newest Nforce driver set.

Also, so far, in World In Conflict I am yet to see an fps-change, so I guess when selecting SLI-mode, it doesn't really do so.
January 31, 2011 6:08:04 AM

pardon these double- and triple-posts, but I am not allowed to edit any earlier messages.


what I saw in my system settings when SLI was activated as per Nvidia control panel was that the first card runs x16, while the second runs x8.

As I have almost no experience with SLI, I don't know if that's normal or not...
February 2, 2011 11:08:01 AM

hey clarkjd,

thank you, that's the kind of input I needed.

I tried changing my previous post after the initial anger had ebbed off, but the forum wouldn't let me.


anyway, I'll probably go for a 850W-psu with 4x6pin-connectors.

if I had known that in advance, I'd have simply bought a much better video card :) 
a c 172 Î Nvidia
February 2, 2011 5:05:58 PM

skunkrider said:
hey clarkjd,

thank you, that's the kind of input I needed.

I tried changing my previous post after the initial anger had ebbed off, but the forum wouldn't let me.


anyway, I'll probably go for a 850W-psu with 4x6pin-connectors.

if I had known that in advance, I'd have simply bought a much better video card :) 

Use the "quick edit" function.
February 2, 2011 10:00:20 PM

I would be looking at your PSU.

I run my 9800gx2 on a 2kw PSU.

I have alot of other stuff in but for that config I'd be thinking more along the lines of a good quality 1kw psu min.
a b Î Nvidia
February 2, 2011 10:38:28 PM

Dreamwind said:
I would be looking at your PSU.

I run my 9800gx2 on a 2kw PSU.

I have alot of other stuff in but for that config I'd be thinking more along the lines of a good quality 1kw psu min.


2kw? That would have to be a dual phase unit as most wall outlets are only rated for 1.5kw. As for the psu that you linked in another post that brand is not commonly known and questionable as far as quality is concerned. You do not need 1k for just two meager 9800gtx in two way sli. 700w~ from a high quality unit is more than enough.
February 2, 2011 11:01:24 PM

I think you got a bit confused there mate.

I've not recommended any brand.

Wall outlets is country specific, 2kw isn't a problem over here.

I always go on the concervative side as far as wattage.

And it's not just the power rating that's important it's the voltage stability off the rails, especially on a sli setup on a gaming rig.

But like I said as far as this system builder goes I'd always put in a 1 kw especially for the 9 series they love power.

Basically you can never have too much but you can sure as hell have too little. :) 
February 3, 2011 5:34:34 AM

alright... so I guess there's not that much of a difference between 850W and 1000W, price-wise.

Also, I bought my PSU in late 2008, and it has lived through many many system changes and sometimes looked like the probable culprit when the system wouldn't start up and I had to cold-restart in order for the computer to work... :sarcastic: 

it'll have to be a new PSU then. :??: 
a c 172 Î Nvidia
February 3, 2011 4:17:03 PM

Dreamwind said:
I think you got a bit confused there mate.

I've not recommended any brand.

Wall outlets is country specific, 2kw isn't a problem over here.

I always go on the concervative side as far as wattage.

And it's not just the power rating that's important it's the voltage stability off the rails, especially on a sli setup on a gaming rig.

But like I said as far as this system builder goes I'd always put in a 1 kw especially for the 9 series they love power.

Basically you can never have too much but you can sure as hell have too little. :) 

I'm running more than the OP on a 620w PSU, 1kw is just daft as the 9 series do not need that much.
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