I have got EXACTLY the same problem, my second GTX670 is not detected on cold boot, once restarted, it working perfect. I've tried everything, new ram, new motherboard, new SLI bridge, new OS install, clear CMOS... but allways with the same result. Ive read many many solutions on forum but nothing works for me... Can anybody help?
My system:
AsRock Z77 Extreme6
Intel i5 - 3750K
8gb g.skill ripjaws x ddr3-1600
SLI 2x Asus GTX670 Direct CUII
Windows 7 ULTIMATE 64bits
Aerocool X-treme 1100W PSU
Thx!