You're giving Intel graphics as a pro for servers using OpenCL? Either way, I don't know about this set-up, but next year a set-up with Cortex A15 and Mali T658 will have shared cache between CPU and GPU, which should be a lot more efficient than anything Intel or even AMD has today regarding GPU compute. From what I understand cache "latency" between CPU and GPU is a pretty big problem in the desktop space, and this ARM concept should make it a lot better.
> Cortex A15 and Mali T658 will have shared cache between CPU and GPU, which should be a lot more efficient than anything Intel or even AMD has today regarding GPU compute.
Intel's had cache (last level cache, LLC in the diagram below) since January, 2011:
http://www.cnx-software.com/wp-content/uploads/2011/11/arm_s...
The "Little CPU" is supposed to be the lower-power Cortex A7. Canonical is very aggressive about supporting ARM chips.