ATI Radeon HD 4870 Mac Edition 's Advantages
Larger VRAM bandwidth (108.8GB/s vs 98.50GB/s)
608 additional rendering cores
NVIDIA GeForce GTX 550 Ti 's Advantages
Released 2 years and 2 months late
More VRAM (1024GB vs 512GB)
Lower TDP (116W vs 150W)