Comparison of GIGABYTE Radeon RX 580 Gaming 8G MI video card vs ASRock AMD Phantom Gaming D Radeon RX 580 4G OC video card by specs and benchmarks. GIGABYTE Radeon RX 580 Gaming 8G MI runs at 1.257 GHz base clock speed and has 8 GB of GDDR5 memory, while video card ASRock AMD Phantom Gaming D Radeon RX 580 4G OC runs at 1.257 GHz base clock speed and has 4 GB of GDDR5 memory. The weight is different, -- vs --. The TDP of the first video card is 185 W, and the second is 185 W . Compare the benchmark results to find out which video card is better.