Slimjet is lightest, internet explorer the second, palemoon third
Chromium 32 bit is fourth, and thats cent browser with memory purge
( when using cent on 64 bit os, you should go for 64 bit browser aswell)
Just my opinion.
Currently im using basilisk browser from palemoon devs, because of familiar old school interface + privacy over firefox core + extensions like bitwarden + ublock origin support:emoji_punch: and whats the best, forticlient webfilter works with it ( with palemoon doesnt)