NVIDIA GeForce GTX 660 Rev. 2 's Advantages
Larger VRAM bandwidth (144.2GB/s vs 56.00GB/s)
448 additional rendering cores
AMD Radeon 550 's Advantages
Released 2 years and 7 months late
Boost Clock has increased by 15% (1183MHz vs 1032MHz)
Lower TDP (50W vs 140W)