PHP Memory Limit vs. WP Memory Limit

I’m using TPC! Memory Usage Settings to monitor my installation’s memory usage.

The plugin displays ‘WP Memory Limit’ which I know is set by the wp-config.php. It also displays ‘PHP Memory Limit’ which I’m guessing is set by the server host in the php.ini

This may be a dumb question, but is the ‘PHP Memory Limit’ the amount of memory I could possibly dedicate to ‘WP Memory Limit’?

For instance, if I have a ‘PHP memory limit’ of 1000MB, can I (should I) set my wp memory limit to 1000MB?

Sidenote: The site is for a big website with lots of different operations, so many (necessary) plugins are installed and many users (up to 10) can be on making edits at any time.

wp-config.php sets the memory limit for the specific WordPress site which has that file. php.ini will effect your whole server. The php.ini is the parent setting, and so you can set WP to whatever you want within php.ini‘s range.

It’s also importan to note there is a WP_MAX_MEMORY_LIMIT where you can define a max amount of memory WP should use, especially if you have plugins gobbling up all the memory.