Comparison of AMD Radeon RX 660M video card vs AMD Radeon HD 8400 video card by specs and benchmarks. AMD Radeon RX 660M runs at 1.900 GHz base clock speed and has 8 GB of memory, while video card AMD Radeon HD 8400 runs at 1.900 GHz base clock speed and has 2 GB of memory. The weight is different, -- vs --. The TDP of the first video card is --, and the second is -- . Compare the benchmark results to find out which video card is better.