Solved by Windstalker in post #3 
              
              
                Thank you very much for your reply. 
I rechecked everything and now it seems to me that everything works as it should. 5000000 parameters of Floats should take about 20 Mb and I guess it’s my fault that I can’t add numbers >_<. So in total about 600 Mb for PyTorch init + about 100 Mb for each net wi…