Which Amazon EC2 instance for Deep Learning tasks?
I think the differences and use cases are well pointed here. As far the workload, there are features which help you optimise it. According to the official documentation, you can try:


For persistency, 


  sudo nvidia-smi -pm 1

Disabling the autoboost feature


  sudo nvidia-smi --auto-boost-default=0

Set all GPU clock speeds to their maximum frequency.


  sudo nvidia-smi -ac 2505,875