9800GT SLI problems on MSI mobo

[HAFSIX]

So I have a old MSI P6N SLI platinum that I am trying to get a set of BFG 9800 GTs to SLI up on. Screen wont come on when SLI is set up. Each card works individuality, drivers rolled up and down, tried multiple SLI bridges, looked though the bios, nothing. It cant be the PSU since the cards are all though the PICe slot and have no 6 pin power right ? Also the slot changes from 16x to 8x 8x in SLI ...could it be the cards cant run at that bus speed ? I just assumed the second PCIe slot was working since both GPU fans came on but no display.

 

[swifty_morgan]

you tried running each card in another pci-e slot ? there may be a BIOS setting for the slots. I know my old asus board did. cards will run 8x8. that's not the problem. what IS the power supply....... and don't just say 500 watts.

 

[HAFSIX]

http://www.newegg.com/Product/Product.aspx?Item=N82E16817171018 (PSU)
But every thing I have read about the cards and like this
http://www.geforce.com/hardware/desktop-gpus/geforce-9800gt/specifications
makes me think and looks to me that 500W would work ?

 

[swifty_morgan]

did you try both cards in the second slot too or just in the first slot ?

where did you get the cards from ?

when running 2 cards I always plugged the monitor in the upper left dvi connection. anything else and it seemed to "route" it's way through the cards before turning the monitor on.

try the other slot with both cards. mobo is old and back them msi were the worst that could be purchased..

 

[HAFSIX]

the MSI board hasten given me to much trouble until this SLI set up. I have tried each card in each slot but to no avail. I always keep it in the upper left especially since the bottom card shouldn't have output, I got them off craigslist. Just being that both cards work separate I would believe them to be fragged.

 

[swifty_morgan]

so, you tried both cards in the second slot ALONE........ leaving the top slot empty ?

 

[HAFSIX]

hey sorry for the long draw. umm yes I did give that a go after you motioned it and to no avail. My last ideas are ether down to something PSU wise, or the SLI switch chip. I do not believe that the second PCI-e slot going to X8 is a problem.