SLI help!

[Matt2]

So my SLI bridge and my second 7800GT came today.

I moved the jumpers from single card to SLI and I installed both cards. Both cards are plugged in.

The system booted up great the first time. It asked me to install drivers for the new 7800GT. I manually pointed to the 82.12 nv4_disp (same as first GT).

WHen the driver finished installing, the scrfeen went blank. Uh-oh, not good.

I rebooted and the post shows up fine, I get the windows splash screen, it appears to be loading fine.

Then when the splash screen disappears, the monitor goes blank and the light turns from green to orange and says "DVI No Signal"

The system doesnt hang because I cna hear the windows chime and ctrl-alt-del reboots the system.

I am at a loss.

Ideas?

 

[fbrdphreak]

Have you removed the 2nd card and booted normally to make sure the first card & rest of system works okay?

 

[Wentelteefje]

Remove your drivers completely (after you booted with one card), and reinstall them when the two are seated... PSU looks fine, that cannot be causing any probs...

 

[Fox5]

When you reinstalled the drivers it probably set the VGA port as primary monitor and disabled the DVI port. You need to go into the driver settings and set the DVI port as the primary output.

 

[Matt2]

Everything works perfect now. Thanks for the advice Wentel.

I just booted with one card, uninstalled and used driver cleaner. Rebooted with both cards, installed drivers and we have lift off!

12130 3dmarks first run 468/1200.

Now that we've got that settled.....

I'm using coolbits to OC the cards. I set the OC to 500/1200 (I know both cards will do these speeds), but 3DMark reports the VGA clock speed at 468mhz, the default was 470.

Is there something I dont know about using coolbits and SLI? The memory overclocked fine to 1200, but the core clock doesnt change.

 

[moonboy403]

you have to oc the 2 cards independently to the same clock speed

first, you disable sli

1) then turn off the system...plug the monitor cable to the 2nd card
2) start the system (your monitor wouldn't display anything)
3) wait till window loads up
4) unplug the cable from 2nd card and plug it into the first card
5) right click on desktop/properties/settings
6) click on the shaded 2 in the picture
7) click the box that says "Extend my Windows desktop onto this monitor and then click apply
8) now click on advance/geforce 7800 gt
9) now you should see 2 7800 gt tabs
10) oc the two cards independently to the same speed
11) finally...enable sli and you're good to go!

 

[Matt2]

Originally posted by: moonboy403
you have to oc the 2 cards independently to the same clock speed

That's what I thought, but there is only one clock frequencies tab in the driver panel and there is no option to switch between GPUs.

Also, how come the memory overclocked but not the core?

 

[moonboy403]

follow my method and you would see 2 tabs

 

[Wentelteefje]

Could be a 3DMark bug... Try installing RivaTuner or so, and see what it reports...

 

[Matt2]

so you have to repeat this method every time you wanna change the clocks moonboy?

 

[moonboy403]

another method is to flash both cards

 

[Matt2]

Originally posted by: moonboy403
you have to oc the 2 cards independently to the same clock speed

first, you disable sli

1) then turn off the system...plug the monitor cable to the 2nd card
2) start the system (your monitor wouldn't display anything)
3) wait till window loads up
4) unplug the cable from 2nd card and plug it into the first card
5) right click on desktop/properties/settings
6) click on the shaded 2 in the picture
7) click the box that says "Extend my Windows desktop onto this monitor and then click apply
8) now click on advance/geforce 7800 gt
9) now you should see 2 7800 gt tabs
10) oc the two cards independently to the same speed
11) finally...enable sli and you're good to go!

Problem:

WHen Windows boots and I switch the monitor cable from the second card to the first card, the monitor tells me I have no signal.

SLI is disabled.

THe only way to get picture is to reboot with the monitor cable in card one! I can't switch from card 2 to card 1 and get a signal.

ideaS?

 

[moonboy403]

hmm....there are 2 slots on each card

try both slots in the first card when you're switching back

 

[Matt2]

Well, I still cant get it to work. My monitor refuses to display anything using the method you gave me moonboy

Do you think the fact that the two cards have different default clocks (445/1070 vs. 470/1100) is causing me not to be able to overclock using coolbits?

 

[moonboy403]

sli will choose the lowest common clock to run

when you use coolbit...you're only ocing the primary card

 

[Matt2]

that just doesnt make sense to me though.

Well two things dont make sense to me, maybe you can shed some light:

1. If SLI chooses the lowest common clock, why is my default 470/1100 and not 445/1070??? I have a 515 and 516 eVGA GT.

2. If coolbits only clocks the primary card then why does the memory show a overclock @ 1200 in 3Dmark but the core stays default? I think this is the issue that's bugging me the most. Coolbits is overclocking the memory on both cards but not the core on both cards? Kinda strange.

Sorry, if I seem like a n00b, first try at SLI!

 

[moonboy403]

use rivatuner to monitor the clock speed

3dmarks often display incorrect clock speed

 

[Matt2]

ok, so I'm assuming my only option is to BIOS flash both cards to the speed I want?

Nibitor and nvflash should do this right?

 

[moonboy403]

yea

 

[Wentelteefje]

Are you sure you want to start playing with the BIOS settings of your cards? You can't even get them to work properly... Like I and moonboy403 said, try RivaTuner or another overclocking tool, and see how these fare...

 

[Viper96720]

You are moving the cable from the monitor over to the other card? When your using it as a single card.

 

[jEnus]

I don't have a clue why you'd have to follow moonboy403 instuctions in order to o/c both cards. I have had SLI GTs and GTXs and overclocked both through coolbits.