Coming straight to it - in my perception, performance-wise ranking would be →
1. Microsoft Edge
2. Google Chrome
3. Mozilla Firefox
Although Firefox is a RAM guzzler and can get excruciatingly slow, I made Firefox my primary browser after I got fed up of Google AMP, was surprised to so many useful features in Firefox, such as sending tabs across Mobile ↔ Desktop.
Edge has done a pretty decent job, thought I have some issues with their freezing tabs and recently introduced vertical tabs.
I had some issues with Firefox memory usage quite a while ago, tweaking about:config and using the Auto Tab Discard addon made it much better. IIRC the about:config changes were changes to various cache setttings, but one of the more surprising things was that not having disk cache enables significantly reduced memory usage, no idea why, maybe Firefox's bookkeeping code for stuff cached on disk used a lot of memory for some reason. This is just what worked for me, so YMMV, it only might work for anyone else.
One of my bigger annoyances with Firefox at the moment is that it writes to the cookies.sqlite and cookies.sqlite-wal files consistently every few seconds. This writing all the time behaviour has led to Firefox being called a 'SSD killer' a few years ago when SSDs were not as durable as they are now. Every chance I have tried on the about:config settings to try and fix it hasn't worked, got rid of session restore etc, no dice. It looks like I will have to put the Firefox profile directory on a ramdisk to fix this, softlinking the password files to the HDD, because they are the only thing I care about getting written to disk straight away.
Apropos of auto discard add-on, is it made by Firefox or at the very least verified by them?
TBH, I am wary of using any plugins or add-one, since they might slow down the browser.
Currently, I have only Grammarly plug-in installed.
Might I enquire what changes did you perform on about:config to speed up your browser?
On that page it says that it is recommended and that "Firefox only recommends add-ons that meet our standards for security and performance.". I have had no problems with any performance issues with it. However, you have to be very careful with it and make sure that if you are filling out a form or something that you tell the addon to keep the tab. Auto Tab Discard has the options to keep a tab for the session, or always keep tabs for a specific site. Just make sure it keeps the tab for a page that you are writing something on, otherwise you might lose information not submitted. I am not sure about this, I don't remember testing it, but just be safe.
As for the about:config settings, I believe they were these two:
browser.cache.disk.enable = false
browser.cache.memory.max_entry_size = 512
The first one is obvious. The second one limits the cache to only storing it if the entry is less than 512KB. My reasoning to change was that it should this to a smaller value was that smaller things like tiny images would be used across pages whereas larger things are less likely to be.
One I didn't change was browser.cache.memory.capacity, look it up if you want. From memory, the one that really seemed to matter was browser.cache.disk.enable to false, I really don't know why.
I have always thought that the fastest browser is the one I don't use daily. That the fact that my daily browser has 50-100 tabs open makes the browser I switch to seem much faster.
Unless of course the first thing that happens when i switch is that the seldom used browser asks me to restart it to install an new version.
I haven't tried the new Edge, but the old Edge used to get into states where button presses on the controls would be queued. That's not great for performance perception. (Incidentally, firefox on Android sometimes gets there too, especially after viewing npr org, hmm)
1. Microsoft Edge
2. Google Chrome
3. Mozilla Firefox
Although Firefox is a RAM guzzler and can get excruciatingly slow, I made Firefox my primary browser after I got fed up of Google AMP, was surprised to so many useful features in Firefox, such as sending tabs across Mobile ↔ Desktop.
Edge has done a pretty decent job, thought I have some issues with their freezing tabs and recently introduced vertical tabs.