2x EVGA 780Ti SC, Enable SLI = BSOD

S

Syphon Filter

2[H]4U
Joined
Dec 19, 2003
Messages
2,597
Hi Guys,

I've just put the system in my sig together. For the most part everything went pretty smoothly. The build went without hitch and I've got my OS and a bunch of games etc. installed.

All my motherboard drivers are installed (Chipset, MEI & Audio), I'm running the latest WHQL nvidia drivers and Windows is fully updated too. There are no unknown devices showing in Device Manager. I have also upgraded the motherboard BIOS to the latest available from Asus (1102).

Everything seems fine.

However, when I select the "Maximise 3D Performance" option in the nvidia control panel and hit apply my screen goes black and then throws a BSOD. While it's doing this I can hear the Windows "ding-dunk" followed by a "ding-dong" as if hardware has been removed/installed.

After a reboot the nvidia control panel shows SLI as enabled :confused: What I don't know is how I can check that SLI is actually working, is there a utility or something I can use to see the utilisation of each card while gaming or something?

IIRC disabling SLI doesn't cause any issues, it just does it's thing (I can't remember the sequence of black-screen/sounds etc.) and seems fine.

Either way, I still need to be able to enable/disable SLI without invoking BSODs because, as I've been finding, some games support it while others don't!

In terms of power connections I have the following connected:

ATX - 24-Pin
CPU - 8-Pin & 4-Pin
Mobo - Molex, I think this is an Asus specific thing
780Ti - 6-Pin & 8-Pin (both connections on same modular output from PSU)
780Ti - 6-Pin & 8-Pin (both connections on same modular output from PSU)

I have the Asus supplied SLI bridge installed (it's the only one I have) and everything is at "stock" (the SCs are factory OCd).

Does anyone have any ideas what might be causing this? This is my first multi-GPU machine so I'm learning as I go here, any help would be much appreciated.

Cheers,

sf.
 
Last edited:
Wild guess is it's something about the way you installed 8.1. Did you use the UEFI installer? Do you have the internal graphics disabled?

I think probably when you do the restart and it says sli is enabled, it is.

You can check a lot of ways but Unigine Valley would give you like idk 100fps with 1 gpu and 170 with both working. You could run a benchmark and have a monitor program like HWinfo64 running in the background and it will show peak gpu usage for both cards.
 
Hi...

You may be onto something here because I have no idea what UEFI Installer is?!

I just made a bootable USB stick with Win8.1 on it, stuck it in and it booted and allowed me to install. I have not manually disabled the onboard GPU either (which I assume is a BIOS/UEFI thing that I need to do).

Do I need to go ahead and reinstall Windows? Also, should I disable Windows Defender when installing drivers etc.?

Sorry, I'm a bit out of the loop on a lot of this stuff!!!
 
So I've managed to do an UEFI install and I think it might have fixed the issue.

Thanks for your post. It put me on the right track and, after a few hurdles, I managed to get my system installed in UEFI mode.

I've enabled/disabled/re-enabled SLI a few times and it seems to work now!

Thanks again.
 
You must log in or register to reply here.
Back
Top