NVIDIA GeForce GT 640 's Advantages
Lower TDP (65W vs 180W)
NVIDIA GeForce GTX 1080 's Advantages
Released 3 years and 11 months late
Boost Clock1733MHz
More VRAM (8GB vs 2GB)
Larger VRAM bandwidth (320.3GB/s vs 28.51GB/s)
2176 additional rendering cores