Just to let you know, the problem has re-occurred.
Now with 40.0.2308.62 Stable, still with Windows 7 64-bit, 8 GB RAM.
Do more on the web, with a fast and secure browser!
Download Opera browser with:
Blink with extensions is getting more comfortable -- my username recalls the days of the download fitting on a floppy.
Session Buddy (a Chrome extension) recorded over 400 tabs open before the problems, so maybe I was flying too close to the sun.
Thanks: I installed https://ftp.opera.com/pub/opera/desktop/36.0.2130.32/win/Opera_36.0.2130.32_Setup.exe into a separate folder, not into a sub-folder of the usual installation directory, and it's been running fine for over a day.
I was somewhat surprised, though relieved, to see it had imported my bookmarks, speed dial and extensions from the prior runaway Stable installation.
Win7pro 64-bit, 8GB RAM.
With all extensions disabled and only speed dial open, one of the Opera processes increases consumption of RAM until a crash occurs within a two minutes. Crashreporter log is saved, but as an empty file.
This first occurred with Stable, a week or two ago. Re-installing into a new folder didn't help so I've been using Developer, which has been OK until today. All extensions have now been removed, and it's still happening.