XFX 780i unstable with SLI

[jacoro1]

Hi

I'm having an issue getting SLI to work properly on my XFX 780i board. I have 2 8800GTS 512's. The system is completely stable with either card by itself, but when running in SLI the screen will freeze or go black either during OS startup or when initializing games or video playback. Sometimes it will work correctly in SLI for a few minutes before this happens. This will happen even if SLI is disabled in the nVidia control panel if both cards are plugged in. This system is not overclocked. the PCI-E power connectors are plugged in. Also I plugged the cards into a friends 650i board and it worked fine in SLI, which leads me to believe it's an issue with the motherboard. However, I'm having the same issue after replacing the motherboard with one from a different store.


So far I have taken the following steps to troubleshoot:
Updated BIOS
Updated drivers for motherboard and videocards. Tried Beta drivers too.
Reinstalled OS
Replaced motherboard
Tried 3 PSU's (up to 1000W)
Tried different RAM, in single and dual channel
Removed sound card
Unplugged HDD's except one containing OS

My system consists of the following:
XFX 780i SLI
e8400 CPU
2x BFG 8800GTS 512
2GB CORSAIR DOMINATOR 8500C5D RAM
COOLERMASTER 850 WATT PSU
SOUND BLASTER X-FI
VISTA ULTIMATE 32-BIT
76GB WD RAPTOR HDD
500GB SEAGATE HDD
PIONEER SATA DVD-RW

The case is well ventilated and temps are good. I'm at a loss now...
Thanks in advance for any help.

[xfxsupport]

What happens if you run SLI without using the SLI bridge? Its rare but I have seen where the bridge can cause issues. Let me team with an engineer to see if they have heard of such an issue, especially since you pretty much covered most of the troubleshooting (one stick or ram, disconnecting hd's and testing other components).

[xfxsupport]

Also, just for arguments sake, try downclocking the system RAM to 667mhz and let me know how that works out.

[david.hill64]

I had a problem with my Creative X-Fi sound card causing video problems: have you updated the creative drivers as well? (Mine is Vista 64-bit so may not be related to your problem).

[jacoro1]

Thanks for the suggestions

I have the newest x-fi driver installed, and have tried it without the card or driver installed with no effect.

Removing the SLI bridge caused it to freeze on an orange screen about 15 seconds after launching 3dmark. Setting RAM to 667MHz made no difference.

I tried disabling Aero in Vista, and it worked fine in SLI for hours. As soon as I re-enabled Aero it bacame unstable again. I'm hoping there's a way to resolve the issue with Aero turned on, as standard mode seems to be particularly ugly with SLI when moving windows around. At this point I don't know if it's an issue for XFX, nVidia, or Microsoft.

Thanks again for the help

[hollowgr4m]

hi i have an EVGA 780i, and i don't know if this is the same problem but there is an issue involving crashes and artifacts during video playback. So far there is no answer as to why and neither evga nor nvidia have helped, if anyone from xfx reads this i'd love to know what you think.

here is a massive thread on the evga full of people with this problem

http://www.evga.com/forums/tm.asp?m=253891&mpage=4&key=&

[hollowgr4m]

hi, i have an evga 780i and there is a problem similar to this with crashes and video corruption during video playback, nvidia dn evga so far haven't been able to help and if any exf guys read this i'd like to hear what they say


here is a thread at the evga forum full of people with this problem and no solution

http://www.evga.com/forums/tm.asp?m=253891&mpage=4&key=&

[computerlizzard]

Jacoro1,,, did you get this figured out?

I have a very similar system build and having stability issues all over the place.

XFX nForce 780i SLI MB
Intel Core2Duo 3.0Ghz E8400
4 1Gb OCZ SLI OCZ2N1066SR2GK
2 XFX 8800 GTS with SLI
Zalman CNPS 9500a w LED
Creative Audigy 2 Zs
Logitech Z550 5.1 Surround Sound Speaker System
Antec Tru Power Quattro 1000w
Antec Nine Hundread Case
Seagate SATA 500GB HD
Pioneer IDE Optical Drive
Windows XP 32bit
Dell 24" 2407FPW-HC

[srpeters18]

If I had to guess, your stability issues are caused by your 4x1GB OCZ mem. Make sure you're running at least 2.1v, maybe even 2.2v and a 2T clock rate.