Watching top is not my favorite hobby...
Opera9.64 is currently VSZ=63000 9.7% and socat is VSZ=2080 0.8%
( while I was Xmas shopping, socat was once 1.3% ).
I have turned off sound, flash, plug-ins, auto-refresh, and other oddities, to gain as much speed as possible. It is much faster than Firefox, and nearly as fast as Midori.
I tinkered with some of the horrible add-on widgets. Waste of resources.
I prefer to use the old-school HOSTS file filtering simply because I can easily keep the HOSTS updates in sync with my router-filter tables and share that same file on all PC/laptops without regard to what OS or browser is used. That eliminates MOST of the crap. However, I still subscribe to specialized filters for the sub-teen grandchildren, so I can let them play safely on the web.
Another nifty filter is WOT, a very popular Firefox add-on. It maintains a user-rating database and shows red/yellow/green scores on all web pages, Cute & handy.
I often preach that virus-protection programs are practically useless without effective filtering.
Anyway,,, back to performance. Are these numbers inline with your observations ?
Do you have any silver bullets that make Opera even faster ?