NVIDIA GeForce GTX 780 Ti 6 GB 's Advantages
More VRAM (6GB vs 2GB)
Larger VRAM bandwidth (336.6GB/s vs 112.0GB/s)
2368 additional rendering cores
AMD Radeon RX 550 's Advantages
Boost Clock has increased by 27% (1183MHz vs 928MHz)
Lower TDP (50W vs 250W)