So to sum it up, you bought 2 - GTX580's for a game that doesn't support multi-gpu setups, and you're asking if another multi-gpu setup would be better.
For a game that is CPU bound.
Do I have that right?
Edit:
Minimum:
* OS: Windows XP (SP3)
* Processor: Pentium D 3.4GHz (or equiv)
* Memory: 1 GB RAM
* Graphics: nVidia GeForce 7200/128MB or equivalent
* Hard Drive: Approx. 16GB hard drive space
* Sound: DirectX 9.0c or compatible Sound Card,
* DirectX 9.0c
* Mouse and keyboard
Recommended:
* OS: Vista/Windows 7 (64 Bit),
* Processor: Core 2 Duo (or equivalent),
* Memory: 2 GB RAM,
* Graphics: nVidia GeForce 8800 (or equiv)
* Hard Drive: Approx. 16GB hard drive space,
* Sound: DirectX 9.0c or compatible Sound Card,
* DirectX 9.0c
* Mouse and keyboard