AMDMB has come up with their Computex coverage and has posted some info on the XGI Volari series :

The duo board uses two processors, as you can see above, though they do not work in SLI mode (scan line interleave). They actually work by rendering individual frames into individual frame buffers (memory) in alternating order. GPU1 will render frame 1011 while GPU2 will render frame 1012 and then GPU1 renders frame 1013, and so on. They are using a bridge mechanism between the GPUs where the first GPU is referred to as the primary and then passes on information to be calculated to the second GPU. This is necessary because the AGP bus can only communicate through a single processing source.