only 2 gpu's working under 3-way sli

[mav104]

One of my 8800gtx's is not working under sli. I've tried downloading a different NVIDIA driver but no help. Everywhere I look (3dmark vantage, Vista device monitor, etc.) shows that I have 3 gpu's attached. I downloaded the latest version of NVIDIA Control Panel and in the "Set SLI and PhyX configure" area I can only click the "Maximize 3D Performance" or "Disable SLI" buttons - "Activate all displays" is unavailable. If I click Maximize 3D Performance I get a diagram showing that gpu #2 and gpu#3 are running in sli and #1 has an image of the Sony monitor I'm using for display. This, of course, is the top PCI-E connector and has the HDMI cable connected.

I'd appreciate any ideas you guys might have to solve this problem. Just a few weeks ago I actually had 3-way sli running. It looks like none of my gpu's is defective but #1 works but doesn't want to join the sli gang.

Thanks

 

[happy medium]

Welcome to the forums.

WHat drivers are you using?
Have you tried reinstalling them?
Have you installed anything that required a restart in the past 3 weeks?
Have you tried switching your cards around?

 

[Keysplayr]

Give a little more history. Have they ever worked in tri-SLI? What mobo do you have?