NVIDIA Quadro P620 's Advantages
Larger VRAM bandwidth (80.13GB/s vs 80.00GB/s)
128 additional rendering cores
NVIDIA T400 4 GB 's Advantages
Released 3 years and 3 months late
Boost Clock has increased by 5% (1425MHz vs 1354MHz)
More VRAM (4GB vs 2GB)
Lower TDP (30W vs 40W)