Can someone please help me out with my 7800 GTX SLI setup?

[ozziegn]

alright, here's the deal.

I just bought my second BFG 7800 GTX to run in SLI mode with my DFI Ultra-D SLI board along with my X2 4400+ CPU.

I initially had some problems getting the display to even come up in Windows XP but thats fixed. so I then decided to run 3DMark 2005 to see what kind of differences I'd seen between one video card and two.

but to my surprise, my scores went DOWN from 8915 (with one 7800 GTX) to 8600 (with two 7800 GTXs). now what the heck is that all about???

everything is showing okay in my display properties. it shows my display as a multi-GPU setup and I can view each GPU's temp and everything. I didnt know weither to use the GPU load balancing so I tried it with and without but that didnt do nothing for my 3DMark score.

I know it cant be a power supply issue because I just bought an OCZ 520W Powerstream which is supposed to be one of the best PSU you can buy. so right now I'm clueless as to whats going on.

so can someone throw me a lifeline or two as to why I'm getting less performance now than I was before with only one video card? I sure hope I just didnt throw $500 away because if I did, I'm going to be sick to my stomach... :(

[Rotarian_SC]

It sounds to me like you didn't change the on the board settings for SLi. You have to physically move stuff on the board. For the DFI I think there are a bunch of jumpers that you have to switch so that it will do SLI right. Also make sure that the BIOS settings are set to have SLI enabled.

[Mustanley]

^^^ correct

There are six (2 rows of 3) jumper sets that need to all be moved down one pin (towards PCI-E) slot two. Then you can enable the SLI checkbox in the nvidia control panel. You will have to reboot one more time after checking that box.

[ozziegn]

okay, everything is just fine now. I did remember to change the six jumpers on my DFI board to enable the SLI feature so that wasnt the problem.

what was the problem was the fact that I was using the 77.72 drivers and I needed to use the 77.76 drivers instead.

I think its a damn shame that I have to use BETA drivers on a $1,000 video card setup but oh well. at least it now works and I'm happy.

thanks for the help guys. :)

[Mustanley]

Can you overclock with the 77.76 drivers in SLI? I had to revert back to the 77.72 drivers because it would not allow me to overclock my 6800s with the beta drivers. But SLI works fine in 77.72 for me as does overclocking.

[ozziegn]

I'm O/Cing my 7800 GTXs just fine with the 77.76 BETA drivers.

[Rotarian_SC]

I can OC my 6800gts in SLI with the beta drivers as well.