Solved by ragnaarok in post #5 
              
              
                Ok, I took the day to debug, many informations here: 
(1) The drop in max batch size varies. And ofc when I increase the batch size, the training is longer so it doesn’t solve the problem 
(2) I managed to rollback my nvidia-driver. I followed this tutorial ( apt - Ubuntu 18.10 : How can I install a…