update: this question is related to Google Colab\'s \"Notebook settings: Hardware accelerator: GPU\". This question was written before the \"TPU\" option was added.
Google Colab resource allocation is dynamic, based on users past usage. Suppose if a user has been using more resources recently and a new user who is less frequently uses Colab, he will be given relatively more preference in resource allocation.
Hence to get the max out of Colab , close all your Colab tabs and all other active sessions, reset the runtime of the one you want to use. You'll definitely get better GPU allocation.