Server settings to improved Wordpress backend speed

Solution 1:

Memory limit and time limit do not affect speed, neithed does PHP Max Input Vars.

Best option for speeding up backend is to use a proper caching plugin which caches database queries, provides a memory-based store for Object caching and transients.

This will reduce the need to make calls to database, which will speed up operation.

Most caching plugins actually have an effect on backend too, because they implement caching in the levels I mentioned above. Caching plugins that create static HTML files of the site do not affect backend operation.

Otherwise, the question is far too generic to give any specific optimization advice. It all depends on the hosting setup, what kind of plugins are used etc.