Gaming Performance 2
Serious Sam 2

The 78.03 driver isn't compatible with Serious Sam 2 in SLI mode it seems. SFR rendering mode gives no gains, the 1st GPU getting ~90% of the work to do and the 2nd GPU renders the bottom ~10%.
F.E.A.R.

While NVIDIA hardware has a hard time with F.E.A.R, SLI is able to accelerate it well. Two 7800 GTs are able to outrun the other two boards in SLI on the Dual.
Far Cry

The Dual just bangs its head against the CPU limitation presented by the Athlon 64 FX-57 as the others do.