Given Chrome has a larger and more extensive collection of extensions, perhaps users who see differences are running more browser extensions in their Chrome installation, which impacts on performance/power usage?
Certainly interesting to see these assumptions put to the test though, and get some data around them. While it looks like it may have fallen behind again a little, I noticed Firefox's browsing performance on Speedometer caught up for a while, contrary to what I had thought/assumed.
We've seen versions of Safari and Edge that leverage those sorts of APIs to deliver better battery life on their respective platforms, but if you are writing a cross platform browser you may not be willing to do extra work for each individual platform.
Several years ago, Firefox adopted the solution Chrome used of dividing the web browser window into large-ish sections, so you could at least skip redrawing sections that had not changed, but that still leaves you doing unnecessary work, just less of it.
Prior to that, the battery drain using Firefox vs Safari on newer machines with higher resolution displays was very noticeable.
Edit: I guess it's probably this sort of thing https://learn.microsoft.com/en-us/windows/win32/directcomp/a...
Any browser could adopt each individual platform's proprietary graphics APIs, but using the same API everywhere (traditionally OpenGL) is less work.
As pixels per inch and screen size increases, the cost of doing unnecessary rendering work becomes more noticeable.
It's all worth it to me, but there's no doubt a web without tracking and ads would easily double my battery life.
That said, it's been ages since I've last seen an autoplaying video. I only seem to encounter them on American news websites for some reason.
Never, ever venture out on the web without a content blocker.
When running a browser performance benchmark, generally not - the ad block extension adds an overhead to the page. I saw this when experimenting with Orion Browser on Mac, which uses the Webkit engine, but adds support for many Firefox and Chrome web extension APIs.
In experimenting with that, I noticed that enabling extensions and using many extensions during benchmarks could easily impact on scores. Even just an ad blocker like uBO had a measurable impact on a benchmark, from my recollection.
I'll gladly pay the 15 minutes of battery power spent on filtering out that trash.