NVIDIA GeForce GT 640 Rev. 2 's Advantages
Released 4 years and 10 months late
More VRAM (1024GB vs 512GB)
256 additional rendering cores
Lower TDP (49W vs 125W)
NVIDIA GeForce 9800 GT Rebrand 's Advantages
Larger VRAM bandwidth (64.00GB/s vs 40.06GB/s)