Firefox is not a slow browser. While your experience may differ, I think that Firefox is loading the majority of web pages and sites as fast as Google Chrome. At the very least, it is hard to tell a difference.
While you can speed up browsing in Google Chrome, the options that you have are fairly limited when compared to those of the Firefox web browser.
You can configure Firefox so that websites get loaded faster in the browser. I'm not talking about improvements that you only see listed in benchmarks, but real-world improvements that you notice when you load sites in the web browser.
There are however tweaks that have no effect, or even a negative effect on Firefox's page loading performance. This article is about those.
One of the main issues that you will notice when you search for ways to speed up Firefox on search engines such as Google, Bing or Startpage is that most guides are outdated.
How you know that? By noticing that they refer to preferences that are no longer used or use changed values.
Many guides suggested to enable pipelining and related preferences. They may suggest to enable pipelining for normal and proxy connections, or increase the maximum number of requests from 4 to 8.
Research has shown that pipeling has no effect on the page loading time of the browser, at least not in its current form.
According to the researcher, the main reasons for this is that most websites load contents from different domains making pipeling less effective as it could be, and that bottlenecks on the page limit its effectiveness as well.
So, if you enable pipelining in Firefox in hope of seeing huge speed gains, you will be disappointed as there won't be any.
To make matters worse, the suggestion to modify the network.http.pipelining.maxrequests parameter to 8 won't do any good as well, as it is set to 32 in newer versions of Firefox.
Then there are sites that suggest to increase the value of the network.http.max-connections parameter to 64. While that may have worked years ago, it won't work anymore as the new default value of the parameter is 256.
Next we have network.http.max-connections-per-server which many guides mention. The preference has been removed from Firefox making network.http.max-persistent-connections-per-server the relevant preference in Firefox.
So, disabling the hard drive cache and moving the cache to memory should speed browsing up since memory is faster than disk, right?
Not necessarily. First of all, Firefox is already using both caches by default, which means that some cached items are already in memory so that they are loaded from there when needed.
Even if you disable the disk cache, it will be used. One plain and simple example of this is when Firefox's memory cache is full.
There are negatives to going memory cache only in Firefox. Since some items are not cached on disk, they are not persistent. This may increase the page loading time of websites in Firefox after restarts.
I'm not saying it does not speed up things in Firefox, but only if the parameters are right. If you visit a site several times in a single browsing session, you may notice a speed improvement doing so. More if the Firefox is stored on a slow disk, less to none if it is stored on a fast drive like a Solid State Drive for example.
When you minimize Firefox, RAM is swapped out which means that it is reduced and available for other programs and processes on the system.
What is meant by that is that the data is saved to disk for the time being, which can result in a delay when Firefox is restored.
Mozilla discovered back in 2008 that the minimize - swap feature does not really do anything.
The main problem in Windows is that the Task Manager is lying in its interface, and that the minimize action in most applications has a visible effect. But it doesn't really do anything - it only says that the application is now a candidate for being swapped out (that was useful in the Windows 95 days). But when an application touches the memory again, then that part of memory will be marked as active again, and the memory usage seems to grow again (but that's an illusion). Applications that do a lot of stuff in the background will seem to jump right back again, but in reality nothing really changed (look at your hard disk light - it didn't even blink !).
The authors who wrote the guides back in 200x are not really to blame here, as things were different back then. The main issue here is that today's authors are picking up those guides again.
Search engines are partially to blame for that, as they keep old guides at the top of the search results even though that should not be the case, as they are of little use nowadays.
Today's authors who copy those preferences without doing research on the other hand are mostly to blame for that. It is easy enough to write an article about speeding up Firefox using those old guides and the suggestions that were posted in them.