NVIDIA GeForce 7800 GTX 512 's Advantages
More VRAM (512GB vs 256GB)
Larger VRAM bandwidth (51.20GB/s vs 25.60GB/s)
ATI Radeon HD 2600 XT Mac Edition 's Advantages
Released 2 years and 3 months late
120 additional rendering cores
Lower TDP (45W vs 108W)