ATI Radeon HD 5870 Mac Edition 's Advantages
320 additional rendering cores
AMD Radeon R9 270 's Advantages
Released 3 years and 5 months late
Boost Clock925MHz
More VRAM (2GB vs 1GB)
Larger VRAM bandwidth (179.2GB/s vs 153.0GB/s)
Lower TDP (150W vs 228W)