AMD A10-7850K

From: http://www.forbes.com/sites/davealtavilla/2014/01/14/amds-kaveri-apu-with-radeon-r7-graphics-targets-mainstream-power-efficient-computing/
There is a 8-core GCN implementation in Kaveri that consumes a substantial 47% of the  2.41 billion transistor die. Each of those 8 GCN cores has 64 stream processors, for a total of 512.

Based on GCN architecture whitepaper, one compute unit includes 4 separate SIMD units. And one SIMD unit simultaneously executes a single operation across 16 work items.

Processing elements inside one GCN cores.