AMD Radeon R9 M385 's Advantages
More VRAM (4GB vs 2GB)
Larger VRAM bandwidth (76.80GB/s vs 48.00GB/s)
256 additional rendering cores
AMD Radeon RX 550X Mobile 's Advantages
Released 2 years and 11 months late
Boost Clock has increased by 18% (1176MHz vs 1000MHz)