NVIDIA GeForce 840M 's Advantages
Released 5 years and 9 months late
Boost Clock1124MHz
More VRAM (2GB vs 512GB)
64 additional rendering cores
Lower TDP (33W vs 55W)
ATI Mobility Radeon HD 3870 's Advantages
Larger VRAM bandwidth (54.40GB/s vs 16.02GB/s)