AMD Radeon HD 7990 's Advantages
Larger VRAM bandwidth (288.0GB/s vs 256.0GB/s)
AMD Radeon RX 480 's Advantages
Released 3 years and 2 months late
Boost Clock has increased by 27% (1266MHz vs 1000MHz)
More VRAM (8GB vs 3GB)
256 additional rendering cores
Lower TDP (150W vs 375W)