With a google search "best cache limit firefox cached web content" I found the following:
If you read that, it may be of help. Note in particular the greyed 350MB they have at Override, where the User is currently using 5.1MB.
The 350MB is the default as you can see in my own personal example below:
... and that I am using 298MB currently, so might need to adjust.
Bear in mind that the caching has two main functions:
- Speeding up reloading of sites you have visited before and
- Easy access to same when you are working offline
I won't say it is an arbitrary limit, and experts more advanced than I might say there is an optional best limit.
I have been using Firefox since nearly Day One, first under Windows, and now exclusively under Linux, but I can't say that I have really studied caching.
Hope this helps
BTW amount of RAM will impact - I have 8GB and can have 100 or more tabs open before noticing performance degradation, but I try to keep it under 20 and sort the others to bookmarks, or cull/close, lol
Edited - added BTW
Edited by wizardfromoz, 28 August 2015 - 06:42 PM.