This has never been the case for me at all. I write this comment in Chrome because I have it for testing and specific purposes, but I believe CPU and memory utilization advantages of Chromium always have been a myth for the most part. And I am someone that holds a lot of tabs open without rebooting my work machine for days or months.
Browsers are still memory hogs, but at some point you have to decide if you want speed or low memory usage. Fast reaction time or nicely rendered pictures. On a decent machine, not even a fast one, there is no difference. That said, I despise notebooks and usually use towers.