NVIDIA GeForce 840M 's Advantages
Released 3 years and 2 months late
Boost Clock1124MHz
More VRAM (2GB vs 1024GB)
288 additional rendering cores
Lower TDP (33W vs 35W)
NVIDIA GeForce GT 550M 's Advantages
Larger VRAM bandwidth (28.80GB/s vs 16.02GB/s)