I have two Palit GTS 250 cards, and an SLi capable motherboard, GB P55A-UD4, and for some reason I do not have the option to enable SLi. Futhermore, when I start the computer, only the bottom card (Relative to the CPU) will have it's fan running and will display anything. However, if I remove the bottom card and then start the computer, the top card runs fine. I've tried swapping the position of the two cards and it makes no difference. I'm running with a 500W Antec Power supply, 2x 500Gb 7200 rpm HDDs, 4GB DDR3 RAM, Intel Core i5-750 processor. The only possible thing I can see that might be problematic is that my motherboard supports the 2x4 12V connecter, while my PSU only has a 2x2 12V connector. Both cards have 6V PCI-e power. Is there anything I can do to fix this?
Does you m/b have an updated bios ? One of the updates (i have p55 ud4p) fixed dual graphic card compatibility I believe.
Its confusing your explanation of the power connectors. You need 1 6 pin pcie connector for each card. Do you have 1 for each card ?
If not are you supplying two molex to one 6 pin for the second card ?
Hey, thanks a bunch! Updating the BIOS got the fan spinning on the top card, but it still won't let me display anything on the top card unless the bottom one is out. And it still doesn't show up in the Device Manager in windows.
Sorry about the confusion. I do indeed have 1 6 pin PCI-e connector for each card. And yes, for the second card it is two molex to one 6 pin.