I just got a new Sapphire Radeon HD 6870, and when I install it, the card does not show up in device manager. I have installed the drivers for the card, and I have also uninstalled my onboard graphics. I have a nForce 630i / Nvidia GeForce 7100 motherboard (with updated drivers) that has a PCI-E 1.0 slot. In BIOS, PCI-E is the default display. I am wondering if i need to get an updated motherboard in order to use the card. My 9800 GT works fine (PCI-E 2.0). Is it because the 6870 is a PCI-E 2.1 that it doesn't work in the 1.0 slot? I thought PCI-E were reverse compatible so I assumed the card would work. Any ideas? Also using a 550W Corsair PSU.
There are two possibilities: you have run into the PCI-E 2.1 compatibility problem that some PCI-E 1.0 boards have, or you got a bad card. If possible, try running the 6870 in another PC. If the 6870 works on another computer, it's the PCI-E 2.1 compatibility problem. Check your motherboard manufacturer's website for a BIOS update for your board. Some of the boards with this problem will only run 2.1 cards with an updated BIOS. If it is the compatibility problem and there is no BIOS update that addresses this for your board, you'll need to either get a new motherboard that does support the 2.1 cards, or RMA the 6870 and look for a PCI-E 2.0 card. None of AMD's current cards use 2.0, they are all 2.1, so you might have to look at nvidia for a 2.0 card if you need one, or look for an HD 5000 series card that is PCI-E 2.0.