NVIDIA GeForce GTX 680M 's Advantages
More VRAM (4GB vs 1024GB)
Larger VRAM bandwidth (115.2GB/s vs 14.40GB/s)
1024 additional rendering cores
AMD Radeon HD 8550M 's Advantages
Released 2 years and 1 months late
Boost Clock has increased by 12% (850MHz vs 758MHz)