Sorry for the re-post of something I did earlier- hadn't known first posts take several hours to moderate, and ended up posting 2 whole pages back from the present.
Just posting this again, to ensure the issue with high CPU load and extreme lag with hardware acceleration is known:
First: Thank you for doing this for Raspbian Jessie. I've been happily using Chromium 50 for home and work on my Pi 3B for a month now.
Thought I'd try and help out a little with feedback, since there is a fairly major performance difference between Chromium 50 and 51 for me.
On v50, these forums loaded smoothly, and even Google Docs was at least usable in terms of responsiveness. Since the update to v51, I saw hardware acceleration is now enabled. (Mental "Whoohoo!") Sadly, every time I enable hardware acceleration in Chromium Settings, every single page lags. Not just Google Docs anymore, but even these forums. Heck, even the Chromium Settings page- nay, the Chromium menu itself has an awkwardly long pause to load.
Changed my memory allocation to give 256 MB to the GPU and restarted, thinking it'd make a big difference from my usual 64 MB. Nnnnnnope!
Only way to speed it up is to go to Settings and uncheck "hardware acceleration if available."
Any thoughts about why this might be slower with hardware acceleration than without (putting aside that it's a Raspberry Pi, and that might be a reason all its own)?
And is there any additional information it might help to know? If there's anything I can do, please do let me know.
Meanwhile, I'm keeping my browsing solely software-accelerated. The advantages of having the same bookmarks sync on all my computers and phone continue to far outweigh lack of, or lagginess of, hardware acceleration anyway.
EDIT: Forgot to mention the 90%-100& CPU usage whenever I click anywhere inside the Chromium window with hardware acceleration enabled. It's more like 40% if I switch to software acceleration.
Hope it's fine to re-post this, just this once. I don't remember seeing it mentioned in the 2 pages since yesterday, so...
RPi 4B w/ Buster in a toasty little official case, and an RPi 3B w/ Stretch.