P5NE-SLI with Radeon 6870 will not post

Hi,

I seem to be having a problem that others with an ASUS P5NE and newer AMD GPUs are experiencing: I was running a 8800 GTS 320 and recently purchased a Powercolor 6870. After putting in the new card, the system will not post. 5-10 seconds after powering on, I get the one long beep followed by three short beeps, indicating a GPU issue. I have flashed the BIOS to the newest version (1406) and followed the instructions provided by kiethyboyfrance (http://www.tomshardware.com/forum/316515-33-calling-nvidia-650i-chipset-users-compatabilit#t2366478), yet still nothing. I pop in the old GPU the system boots and posts fine. The GPU is powering on (fan to 100%). I also took out the SLI selector card as per the solutions provided by others on this forum.

Other things I have tried include: using the secondary PCI-E slot, reseating the GPU (on a number of occasions), and returning the card to the vendor (I RMA'd it the first time thining the card was DOA).

Here's what I'm running:

Q6600 at stock speeds
ASUS P5NE-SLI
4GB RAM
Powercolor Radeon 6870 1 GB
Seasonic X-660 PSU
Two 7200 RPM HDD

Does anyone have any suggestions? I'm really scratching my head!

Thanks, Andrew

The SLI selector card MUST stay in place. Be sure it is set to the single card position. If that alone doesn't fix the problem, I would try the card in another machine, if possible. It sounds like the card is defective. Btw, I used to have that exact same board. Great budget board for its era.