NVIDIA GeForce GTX 780M Mac Edition 's Advantages
More VRAM (4GB vs 2GB)
Larger VRAM bandwidth (160.0GB/s vs 88.00GB/s)
768 additional rendering cores
AMD Radeon R9 M270X 's Advantages
Released 1 years and 3 months late
Boost Clock has increased by 25% (1000MHz vs 797MHz)