I have tried your suggestion and so far im liking it(11.60 stable build) but since 11.61 is officially out gonna try it there and i have tons of customization to make opera faster at everything on what i do(from UI to internet browse)
also, i found another tip
disabling the “Enable UI Animation” in opera:config makes the UI more responsive
(for power users who likes browsing with 100+ tabs open)
very useful.