NB: This is feedback with a question, not a bug report.
I am evaluating a number of browsers, as I find so many hog massive amounts of memory and CPU. The FF new portable version was seen to use 10G of RAM at one point!
I use the site www.telegraph.co.uk a lot and find it very heavy on resources. With Midori, and only one tab (with telegraph.co.uk) the CPU sits around 15%, on a near new Dell Optiplex, Win10, 32G RAM. Same with many other browsers.
The good news is that I find that, with Brave, the site still takes up a lot of CPU - but only when that tab has the focus!
If you can confirm that this is the intended effect, I will be impressed!