Earlier quoted context omitted.
The only add-ons I use are ones to remove ads. If I didn't have them those ads would easily make the my overall performance much, much worse. I have a custom blank page loaded from SSD that has only a small amount of html5/pure js and it takes maybe 1000ms on an intel i5/3xxx. If I open a new tab without any other windows/tabs open it's very fast, maybe 100ms. A new private tab (doesn't load add-ons or my custom new…
Actually some adblockers were found to increase CPU and memory usage significantly.
And then it was fixed. No reason to assume it still applies, unless you have new data.