Hi, I guess you've figured it out by now, but just in case;
I notice that you've got two gfx cards, so I assume you're using Crossfire...
The culprit is Crossfire - or SLI (yes the same problem occurs with Nvidia cards).
I run two GTX 580 in SLI and see green smoke instead whenever SLI is configured.
I.M.H.O SLI is not utilized by the game, supported, perhaps, if by support you mean that it WILL run even if you've got SLI (or Crossfire) configured. The graphical computing however is not distributed on the multiple GPU's. I smiply switch SLI off when playing CoD... and take the settings down to 'High'. Works for me
Cheers, Tintin