NVIDIA Tesla K80 's Advantages
More VRAM (12GB vs 2GB)
Larger VRAM bandwidth (240.6GB/s vs 48.06GB/s)
2112 additional rendering cores
NVIDIA Quadro P520 Mobile 's Advantages
Released 4 years and 6 months late
Boost Clock has increased by 81% (1493MHz vs 824MHz)
Lower TDP (18W vs 300W)