The script is in my GitHub: my script code Just follow the steps to reproduce [1] with GPU (slow) and [2] with CPU (fast) How to reproduce: [1]: SLOW (with tensorflow-metal installed) == GPU conda create --name lab_slow python=3.9 conda activate lab_slow conda install -c apple tensorflow-deps python -m pip install tensorflow-macos python -m pip install tensorflow-metal python -m pip install gym python -m pip install icecream With [1] I see the GPU burning but the results are very slow and some Information are showed: (lab_slow) fernando@minidefernando restml-muzero % python mymuzero.py             Init Plugin Init Graph Optimizer Init Kernel Metal device set to: Apple M1 2021-07-23 17:10:41.158886: I tensorflow/core/common_runtime/pluggable_device/pluggable_device_factory.cc:305] Could not identify NUMA node of platform GPU ID 0, defaulting to 0. Your kernel may not have been built with NUMA support. 2021-07-23 17:10:41.159108: I tensorflow/core/common_runtime/pluggable_device/pluggable_device_factory.cc:271] Created TensorFlow device (/job:localhost/replica:0/task:0/device:GPU:0 with 0 MB memory) -> physical PluggableDevice (device: 0, name: METAL, pci bus id: <undefined>) 2021-07-23 17:10:41.301535: I tensorflow/compiler/mlir/mlir_graph_optimization_pass.cc:176] None of the MLIR Optimization Passes are enabled (registered 2) 2021-07-23 17:10:41.303570: W tensorflow/core/platform/profile_utils/cpu_utils.cc:128] Failed to get CPU frequency: 0 Hz 2021-07-23 17:10:41.304081: I tensorflow/core/grappler/optimizers/custom_graph_optimizer_registry.cc:112] Plugin optimizer for device_type GPU is enabled. ic| elapsed: -8.216638209 ic| elapsed: -11.702662209000001 ic| elapsed: -7.210992999999998 ic| elapsed: -7.76780325 ic| elapsed: -6.552902541999998 ic| elapsed: -7.051604083000001 ic| elapsed: -7.802484458000002 The time of each iteration is ~7 seconds using GPU. [2]: FAST (without tensorflow-metal installed) == CPU conda create --name lab_fast python=3.9 conda activate lab_fast conda install -c apple tensorflow-deps python -m pip install tensorflow-macos python -m pip install gym python -m pip install icecream With [2] the CPU is used and the speed is good. I got this: (lab_fast) fernando@minidefernando restml-muzero % python mymuzero.py             2021-07-23 17:12:54.201964: I tensorflow/compiler/mlir/mlir_graph_optimization_pass.cc:176] None of the MLIR Optimization Passes are enabled (registered 2) 2021-07-23 17:12:54.204263: W tensorflow/core/platform/profile_utils/cpu_utils.cc:128] Failed to get CPU frequency: 0 Hz ic| elapsed: -0.6991699170000001 ic| elapsed: -1.001101625 ic| elapsed: -0.745720833 ic| elapsed: -0.5131082500000002 ic| elapsed: -0.680853667 ic| elapsed: -0.5841365830000003 ic| elapsed: -0.6107562499999997 ic| elapsed: -0.5290834160000006 ic| elapsed: -1.3289379590000001 ic| elapsed: -0.508716166000001 ic| elapsed: -1.1658726250000004 ic| elapsed: -0.5299397080000006 ic| elapsed: -0.5714273750000007 ic| elapsed: -0.6107442499999998 The time of each iteration is ~0.5 seconds using 1 CPU.