"Last month NVIDIA introduced Optimus as a way for dual-GPU
notebooks to seamlessly switch between the two GPUs but also to
offload the rendering workload to the other graphics processor.
This is somewhat similar to NVIDIA's SLI and ATI/AMD's CrossFire
for splitting the rendering workload across multiple GPUs, but it
has its differences. David ended up developing a proof-of-concept
similar to NVIDIA's Optimus that he is calling "Prime" and it works
with Intel and ATI GPUs.
"David's goals with Prime are to allow a second GPU to render 3D
applications onto the screen of the first GPU, with it being
configurable by the client, and just to handle the rendering side.
This work isn't as simple as his vga_switcheroo implementation, but
it required changes to the Linux kernel and the Graphics Execution
Manager (GEM), the DRI2 protocol, the X Server and DRI2 modules,
and then the actual Linux hardware drivers."