We'll create fresh WordPress site with Memory Usage Monitor installed. You have 20 minutes to test the plugin after that site we'll be deleted.
Once the Memory Usage Monitor plugin is activated, activating or deactivating any other plugin will display the memory used by that plugin. e.g:
Memory usage for WP Memory: 0.02 MB
For accurate memory usage breakdown for each plugin, you must activate or deactivate them individually; you will not see memory usage when bulk activating plugins.