ATI Mobility Radeon HD 5850 Mac Edition 's Advantages
More VRAM (1024GB vs 512GB)
416 additional rendering cores
Lower TDP (30W vs 50W)
NVIDIA GeForce GTX 660M Mac Edition 's Advantages
Released 3 years and 3 months late
Larger VRAM bandwidth (80.00GB/s vs 64.00GB/s)