SRD75

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.

Memory Usage Monitor

Displays memory/RAM usage for each plugin as they are activated and deactivated.

Simon99

Update the WordPress default memory limit. Never run into the dreaded “allowed memory size of 33554432 bytes exhausted” error again!
The default WordPress memory limit is sometimes not enough, especially if you have a lot of plugins installed. This plugin allows you to increase the memory limit without editing any WordPress files.

Change Memory Limit

Update the WordPress default memory limit. Never run into the dreaded "allowed memory size of 33554432 bytes exhausted" error again!

Memory Usage Monitor vs Change Memory Limit