Re: Corssfired Sapphire 6870's 2nd card not recognized.
Change the fan speed of your primary card and see if the fan speed of both changes.
In crossfire, because the clock speeds have to be the same, pretty much everything is shared between both cards, you overclock 1 card, it actually overclocks both, the same is true for fan speed so far as I'm aware
Primary::: Asus M4A79XTD EVO | AMD Phenom II x3 720BE @ 3.4GHz | 2 x 2GB Corsair 1600MHz | XFX HD5770 + eVGA GTX260 Physx | 500GB Samsung F3 + 520GB Storage | Corsair Obsidian 700D | Win 7 Ultimate x64
Secondary::: Asus P5N32-E SLI Plus | Intel Q6600 | 2 x 1GB Corsair 800MHz | Gigabyte 9800GT | 180GB Caviar Blue + 250GB Storage | Win 7 Ultimate x64