3DMark is synthetic but a good way to stress a system. Here we see Hybrid Crossfire is definitely enabled.

The 790GX dominates again though Hybrid Crossfire launches ahead. Luckily there is support for Crossfire in CS: Source.

AMD's QuakeLive is basically Quake 3 in a web browser and does a pretty good job of that. No Crossfire support for an older game and again we see trend with games that aren't the latest they seem to run fairly well all around but the 790GX clearly dominates.

UT3 definitely seems to like the 790GX though the Nvidia card is decent Intel just can't keep up.

Again the 790GX comes out on top in the RTS Company of Heroes although the 780a does well. Hybrid Crossfire is also definitely supported here.