Installed SLI - Computer Fails to boot, constant reset

[atl2rva]

I have done a bit of searching already. Have come up with some situation that sound similar to mine, but nothing to fix the issue yet. This is an existing PC that I plan on setting up with 3 monitors. Everything works fine without a second graphics card installed. Once I set up the new card (exact model as first) the computer fails to boot. All I see is a black screen and a blinking cursor in the top left. If i tap delete it will go to bios. Then after leaving bios the computer just cuts back off. When the computer gives the black screen it will end up resetting itself after about 5 seconds and then the process begins again. I have tried each card individually and they both work using either PCI-E slot. Soon as both are hooked up I have the issue. I have tried with and without the bridge installed. I have uninstalled and reinstalled the latest nvidia drivers and my motherboard is using most up to date bios version. Here are my specs.

Windows 7 64bit Service Pack 2
Asrock Z77 Extreme4 bios 2.9
Intel Core i5-3570K Quad-Core Processor 3.4
(2x)Gigabyte GTX 760 GDDR5-2GB 2xDVI/HDMI/DP OC WINDFORCE 3X Graphics Cards GV-N760OC-2GD REV2.0
EVGA SuperNOVA NEX750B 80PLUS Bronze Certified ATX12V/EPS12V 750W Power Supply 120-PB-0750-KR

Any help would be greatly appreciated.

Update: Was able to get the system working with SLI. It was just a setting in the bios under North Bridge. Had to disable igpu multi monitor

 

[Nordein]

Try checking if your SLI cable is properly attached.

 

[atl2rva]

Try checking if your SLI cable is properly attached.

Thank you for your reply. Could you elaborate if there is something particular I should be doing? It seems pretty straight forward. Slide the bridge on to the SLI connectors on each card. I am using the connectors closest to the input plate of the GPU. Is the bridge directional? There are little white triangles that look like maybe they should line up so I put them that way, but I have tried both directions and it made no difference.

 

[CGurrell]

Normally at this point I suggest the PSU may be the problem, but yours seems to be a good unit. As above, double check the SLI bridge (should go from the first SLI slot on card 1 to the first SLI slot on card 2, and shouldn't be an AMD Crossfire bridge).

Is either card overclocked in any way? If so, restore each OC'ed card to default clocks and try again.

 

[psycher1]

If nothing else comes up try each card individually. And try each PCI slot individually as well, I've seen those go bad before (rarely, but can happen).

Edit: appears you already mentioned doing that. In that case, I'd also be tempted to think PSU, strange as that sounds.
Do you have any other graphics cards? Different models or anything?

 

[CGurrell]

If nothing else comes up try each card individually. And try each PCI slot individually as well, I've seen those go bad before (rarely, but can happen).

He's already tried those (read the top post)

 

[atl2rva]

I think the cards may be factory overclocked, but I have not changed anything. They are identical models that are SLI ready. Bridge is hooked up to first SLI slot on each card. It is an SLI bridge that came with the motherboard and fits on to the SLI slots securely without resistance. Mobo manual list bridge as 1 x ASRock SLI_Bridge_2S Card.

Could I have a bad bridge? Or does it sound more like an issue with PSU? It is a part modular power supply. The 2nd card uses removed VGA cable from the PSU. I can use either the modular VGA power cable or the on built in to the PSU and they both work with a single card.

When I refer to VGA cable it is the one with a 6pin(2x3) and splits off to 8 pin(2x4). I have both cables hooked up to each card so all 4 connectors are hooked up.

 

[vir_cotto]

With the restarting it sounds like a power issue, however the PSU should provide enough power. Both those cards look to hit about 340 watts with the rest of your system probably about 100 more. The 6 pin power connectors from the PSU are they coming off the same line from the PSU?

 

[atl2rva]

If nothing else comes up try each card individually. And try each PCI slot individually as well, I've seen those go bad before (rarely, but can happen).

Edit: appears you already mentioned doing that. In that case, I'd also be tempted to think PSU, strange as that sounds.
Do you have any other graphics cards? Different models or anything?

I do not have any other GPU. Both of these cards are the exact same make and model.

 

[atl2rva]

With the restarting it sounds like a power issue, however the PSU should provide enough power. Both those cards look to hit about 340 watts with the rest of your system probably about 100 more. The 6 pin power connectors from the PSU are they coming off the same line from the PSU?

The power supply is part modular. One cable is built in to the power supply and has both the 6 pin and 8 pin on the same cable. The second cable is one of the modular cables that hook in to the VGA slot on the PSU and again is a single cable that has both the 6 pin and 8 pin connectors on it. Both 6 pin and 8pin are hooked up on both video cards.

 

[vir_cotto]

I think when you are saying VGA you are referring to the 6 pin power connector?

 

[CGurrell]

I think the cards may be factory overclocked, but I have not changed anything. They are identical models that are SLI ready. Bridge is hooked up to first SLI slot on each card. It is an SLI bridge that came with the motherboard and fits on to the SLI slots securely without resistance. Mobo manual list bridge as 1 x ASRock SLI_Bridge_2S Card.

Could I have a bad bridge? Or does it sound more like an issue with PSU? It is a part modular power supply. The 2nd card uses removed VGA cable from the PSU. I can use either the modular VGA power cable or the on built in to the PSU and they both work with a single card.

When I refer to VGA cable it is the one with a 6pin(2x3) and splits off to 8 pin(2x4). I have both cables hooked up to each card so all 4 connectors are hooked up.

Just to be clear, you have a 2 6-pin cables and 2 8-pin (possibly 6+2-pin) cables, and the modular cables are all running from the red ports on the PSU? (Just checking).

You could possibly have a bad bridge but I'm not 100% sure.

 

[CGurrell]

I think when you are saying VGA you are referring to the 6 pin power connector?

The connectors on the PSU are labelled, there are 2 red connectors labelled VGA 3 and VGA 4.

 

[vir_cotto]

Try using more of the modular cables for the 6 pin power connectors?

 

[atl2rva]

I think when you are saying VGA you are referring to the 6 pin power connector?

http://ecx.images-amazon.com/images/I/61qebFs8QYL._SL1000_.jpg

The 2nd Cable listed on that picture. The 8pin that splits off to a 6 pin. Each card has connectors for both 8 and 6 pin connectors.

 

[atl2rva]

I think the cards may be factory overclocked, but I have not changed anything. They are identical models that are SLI ready. Bridge is hooked up to first SLI slot on each card. It is an SLI bridge that came with the motherboard and fits on to the SLI slots securely without resistance. Mobo manual list bridge as 1 x ASRock SLI_Bridge_2S Card.

Could I have a bad bridge? Or does it sound more like an issue with PSU? It is a part modular power supply. The 2nd card uses removed VGA cable from the PSU. I can use either the modular VGA power cable or the on built in to the PSU and they both work with a single card.

When I refer to VGA cable it is the one with a 6pin(2x3) and splits off to 8 pin(2x4). I have both cables hooked up to each card so all 4 connectors are hooked up.

Just to be clear, you have a 2 6-pin cables and 2 8-pin (possibly 6+2-pin) cables, and the modular cables are all running from the red ports on the PSU? (Just checking).

You could possibly have a bad bridge but I'm not 100% sure.

Yes, each 2x 6pin and 2x 6pin+2pin. Second cable shown on this http://ecx.images-amazon.com/images/I/61qebFs8QYL._SL1000_.jpg

 

[atl2rva]

With the restarting it sounds like a power issue, however the PSU should provide enough power. Both those cards look to hit about 340 watts with the rest of your system probably about 100 more. The 6 pin power connectors from the PSU are they coming off the same line from the PSU?

After reading some I found that a single one of these GPUs require a 500wt power supply. Could it be that two of these would need more than the 750wt supply I have installed?

 

[CGurrell]

Probably not. GPU manufacturers overestimate that number a lot due to bad power supplies on the market, as well as to cover themselves. In tests, these GPUs pulled 160W each when being stress tested. That's 320W in total, less than half of your units rated power output.

 

[atl2rva]

Probably not. GPU manufacturers overestimate that number a lot due to bad power supplies on the market, as well as to cover themselves. In tests, these GPUs pulled 160W each when being stress tested. That's 320W in total, less than half of your units rated power output.

Just got home and started working on this again. I came across some new information. I get the exact same issue if I try to boot the computer with onboard graphics and new GPU hooked up at all. I can get in to bios, but black screen where it should be loading windows. I have tried enable "onboard" in the bios for boot priority, but still can not get in to windows. I set it back to PCI-E so I could boot up the computer with GPU installed. So currently it only works with 1 GPU. SLI and On-Board both have the same issue with not being able to boot.

 

[psycher1]

Did you try both cards plugged in but without the bridge? Perfectly doable, you just wont get sli like that. But doing so will tell us if that's the problem or not.

 

[atl2rva]

Did you try both cards plugged in but without the bridge? Perfectly doable, you just wont get sli like that. But doing so will tell us if that's the problem or not.

Yes, I have tried with both cards installed and no bridge connected. Same issue with loop-fail to boot. I posted again in motherboards, because after this post I discovered that the computer will not boot with onboard graphics either. I am starting to just think I have a bad mobo, but odd that everything works perfect with a single GPU installed.

 

[Chaos_Out]

Asrock Z77 Extreme4 bios 2.9

Update: Was able to get the system working with SLI. It was just a setting in the bios under North Bridge. Had to disable igpu multi monitor

OMFG, thank you so much!! Same mobo, same issue. Spent the entire day doing the exact same thing to diagnose it like you did, even bought a new psu , and toyed with bios settings EXCEPT THAT ONE! Saved me from any potential frustration. +10000 to you.

 

[Darkhawk141]

Im having the same problems can someone please tell me how to fix it.

Asus P8Z77 V PRO
corsair hx850
8gb RAM
i5 3570k
EVGA GTX 960 SSC 4GB

Thanks