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Problem enabling SLI with 2 480GTX's

H

hv43082

[H]ard|Gawd
Joined
May 10, 2007
Messages
1,319
Just got 2 480GTX's and every time I select "enable sli", the screen would turn black and the computer requires hard reset to get back into windows. After reboot, sli is still not enabled.

All connections (power connector, sli bridge, etc) are intact. Using Corsair 1000W PSU to power this + i7 920 (oc'ed to 3.78) + 2 HDDs + 2 SSDs + a few fans. Tried latest official and beta driver and get the same problem. I used 2 460GTX in SLI and did not have this problem at all. Yes, I uninstall original driver and ran driver sweeper prior to install both cards and new driver.

I googled around and some people had a similar problem but in their case the SLI option did not show up. My SLI option does show up but enabling it causes the black screen and freeze. Some suggest rolling back Realtek NIC driver (did not work for me). Each card works fine individually.

Need help, please!
 
While that PSU is pretty beefy you've got a overclocked I7 920 and some extra's so it might not be enough considering its hard freezing on you.

http://www.hardocp.com/article/2010/03/26/nvidia_fermi_gtx_470_480_sli_review/7

595 watts during load and thats not counting the rest of the system.

Another possible problem is that you've got some previous driver files interacting and causing the freeze , do a complete uninstall of the drivers (clean driver uninstall from the Nvidia uninstall option) and go into safe mode , user driver sweeper to make extra sure. Then reinstall the latest beta's and see what it does.
 
Did all the steps you recommended already but same problem. Tried install SLI bridge different way, no change. I have 2 2TB WD green +2 Intel SSD's. The OC'ed 920 is on stock voltage. HardOCP did recommend this PSU for 480 GTX SLI.
 
1. Try a third PCI-E slot. The board has at least 3, right? Try a different combination to at least rule out an issue with the motherboard.

2. PSU should be more than fine. The thing obviously isn't even under load when you are just enabling SLI.

3. What if you don't put the bridge on at all. Any change?

Do you have the 460s still lying around?
 
Could be a faulty SLI bridge or even a faulty video card. That PSU should handle that setup (with just a bit to spare) so while its not likely it could still also be a fault.

Unusual problem for sure.
 
I had the same problem. Try to take out the power cables to one card, and see if the other boots. It turns out one of my 480's had died. :(
 
Try updating the motherboard bios, Also try updating the motherboard chipset drivers.

Make sure your monitor is plugged into the primary (top) card when you boot up your pc. How are you connected to your monitor? hdmi/dvi/vga etc..

Finally try lowering down the screen resolution to the lowest possible just before enabling sli and see what happens.
 
hv43082 said:
SOLVED: It is a power issue. According to Corsair http://forum.corsair.com/v3/showthread.php?t=70317, I have both cards on 12V2. Now one on 12V1 and the other on 12V2. Problem solved. Thank you all for the your responses.
Click to expand...

Ugh, that is the one fucked up thing about that PSU. It's literally two PSUs in a box so I guess it is possible to overload one of the PSUs-within-the-PSU if you don't distribute the load "properly" - which you can't do because you don't know what "PSU" the non-modular connectors are connected to unless you Google for the diagram.
 
Yeah you do need to make sure you have them split. It was not just both cards you had on it it was your whole system by the sound of it. I had a 470 in my system (borrowed) to try as physx card and my psu was still fine with a hefty OC on gpu's and cpu. I am looking at getting the new 1200 and waiting to see what amd is going to do next. Now get on with enjoying the cards. :D
 
Godmachine said:
While that PSU is pretty beefy you've got a overclocked I7 920 and some extra's so it might not be enough considering its hard freezing on you.

http://www.hardocp.com/article/2010/03/26/nvidia_fermi_gtx_470_480_sli_review/7

595 watts during load and thats not counting the rest of the system.

Another possible problem is that you've got some previous driver files interacting and causing the freeze , do a complete uninstall of the drivers (clean driver uninstall from the Nvidia uninstall option) and go into safe mode , user driver sweeper to make extra sure. Then reinstall the latest beta's and see what it does.
Click to expand...
read closer because that is for the whole system BUT their results are borked for sli/crossfire. you can see that the system with a single gtx480 is pulling 480 watts but adding a second one only took it to which 595 which is just 115 watts more. same thing for the 5870 which goes from 367 for a single card to just 412 for crossfire. it is 100% clear that the second gpu did NOT get put under full load. I hate when people link to those results and Hard really needs to pull them.
 
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