My benchmark is an extremely simple model for Fashion MNIST: train_images = train_images / 255.0 test_images = test_images / 255.0 model = tf.keras.Sequential([ tf.keras.layers.Flatten(input_shape=(28, 28)), tf.keras.layers.Dense(128, activation='relu'), tf.keras.layers.Dense(10) ]) model.compile(optimizer='adam', loss=tf.keras.losses.SparseCategoricalCrossentropy(from_logits=True), metrics=['accuracy']) model.fit(train_images, train_labels, epochs=10) Yesterday this was running at 10 secs per epoch on my Mac mini M1 16 GB unified memory (and shockingly 2 secs lower than my 16" 8-core MBP with 5500M 8GB) but today that's jumped to 16 secs :( I've tried re-installing Miniforge 3 both 4.10.1-5 and 4.10.2-0 with no difference. I've also installed the latest Xcode CLI tools. Any thoughts? (haven't tested X86 on the MBP yet)