Solved by simaiden in post #2 
              
              
                I think the times are ok for a ResNet50 running in cpu. 
edit: I run your code in a amd fx 8150, and this is the result 
{'eager_mode': [3.1236065919983957,
                2.8740777429993614,
                3.215031881998584,
                3.2408665209986793,
                3.0817273770007887,…