NVIDIA Tesla M40 's Advantages
More VRAM (12GB vs 8GB)
Larger VRAM bandwidth (288.4GB/s vs 192.3GB/s)
512 additional rendering cores
NVIDIA Tesla P4 's Advantages
Released 10 months late
Boost Clock has increased by 0% (1114MHz vs 1112MHz)
Lower TDP (75W vs 250W)