Sli bfg gtx 260 windows 7 black screen after boot

[thebuddha]

Hello,
I am building a new computer but I have run into a slight problem. I planned on having my compy run dual BFG GTX 260 maxcore 55's in SLI but when I started the system, the Windows logo showed up idicating it was starting, then the screen went back-lit black and i couldnt do anything. I tried running one card and it worked fine. Ive done driver sweeps and installed the new drivers, swaped cards, and have run out of ideas on what to do. I keep seeing people say, "just go into the NVIDIA control panel and ennable SLI" but i never make it that far. PLEASE PLEASE PLEASE give me some help.

Specs:
2 BFG GTX 260 maxcore 55
i5 750
EVGA P55 FTW mobo
Apevia 1100W warlock PSU
4gb (2x2gb) ripjaw ram
windows 7 64bit

 

[ssjgokoux2]

Did you bridge the two cards?
Also have you tried testing the cards separately then testing in the other PCI Express slot. Some motherboards require that you hit a switch or move a chip to activate SLI.

 

[thebuddha]

Yes, the two cards were bridged with the SLI bridge that came with the mobo and I have run each seperatly and on each PCIE slot. I did not see a switch or anything to activate it anywhere. The EVGA P55 FTW has 1 PCIE x16/X8 slot and 1 PCIE x8 slot, does this make a difference? I thought it would just clock down the PCIE x16 to x8

 

[thebuddha]

Someone please, I need help with this!!!

 

[gabilondo]

I think the problem is your mobo.These cards are made to run on PCIEx16 connector.The videocards are backward compatible with PCIEx16 1.0 but with PCIEx8,I don"t think so.Did you run a card only,on PCIEx8 connector?

 

[Mousemonkey]

I think the problem is your mobo.These cards are made to run on PCIEx16 connector.The videocards are backward compatible with PCIEx16 1.0 but with PCIEx8,I don"t think so.Did you run a card only,on PCIEx8 connector?

Whilst the problem might be the motherboard it won't be for the reasons you have given as you have made very little to no sense at all and the mother board was reviewed by Hardwarecanuks with GTS250's in SLi and I think you'll find that they are PCIe 2.0 cards thus blowing your theory out of the water.

 

[gabilondo]

I know they are PCIE 2.0 cards,I only said that they are backward compatible with PCIE x16 1.0 and I"m not sure if are compatible with PCIE x8,you just misunderstand me.

 

[gabilondo]

@the buddha,can you tell us what amperage have your PSU on the 12V rails and how many 12V rails?

 

[thebuddha]

It has 4 12V rails and they are at 30A each

 

[gabilondo]

Well that"s a very good PSU to move your cards.You have connected each card with independent rails,because is very important that each card have the juice that require.
Excuse my poor english.

LE:I"ve look at your PSU on the web and it has 2 pcie 2.0 connectors,well the problem is definetly not from your PSU,that"s a good PSU.If you have a friend with same motherboard as yours,give a try to see if it works with your cards.I only see 3 problems that may appear in your situation:1.Bad video card,2.Bad mobo,3.Weak PSU.I suspect the mobo.Do you have the latest BIOS for your mobo installed?

 

[Mousemonkey]

I know they are PCIE 2.0 cards,I only said that they are backward compatible with PCIE x16 1.0 and I"m not sure if are compatible with PCIE x8,you just misunderstand me.

I don't think you understand the difference between PCIe x16 and PCIe x8 because you keep talking about compatibility which has nothing to with the link speed (or bandwidth if you prefer), which is what the x16 and x8 is referring to.

 

[thebuddha]

Okay everyone, thanks for all your help...it turns out i was just an idiot and forgot to update the BIOS on my motherboard. I did that and everything is working perfectly now. Again, thany you all for your help

 

[gabilondo]

Glad to help you,BIOS update is very important when you put new things in yor machine.