I have Opera 45.0 on a Windows 10 laptop with 8Gb of memory.
While I love Opera as a browser, it is eating the memory on this laptop to the extent that even File Explorer fails to open until I shut down Opera. Task Manager is showing nearly 100% memory usage in this scenario.
All is good then for a while but when I re-open Opera, eventually I end up with the same problem.
I'm only talking around 6 or 8 tabs open when this happens and none of them are doing anything stressful like playing video for example.
Without Opera running, memory usage is usually around 40%.

There seem to be a number of posts on Google about fixing the problem but none of them are applicable to Opera 45.0.