NVIDIA Quadro K5100M 's Advantages
More VRAM (8GB vs 2GB)
Larger VRAM bandwidth (115.2GB/s vs 80.13GB/s)
1024 additional rendering cores
NVIDIA Quadro P620 's Advantages
Released 4 years and 7 months late
Boost Clock has increased by 76% (1354MHz vs 771MHz)
Lower TDP (40W vs 100W)