My latest Opera v58.03135.53 on Win 8, 64Bit (But apparently 32 Bit Opera)
Nothing else running beyond Notebook.
Never seen this before:
"OUT of memory
Either Opera ran out of memory or the process for the webpage was terminated for some other reason.
Try reloading the page, or navigate to another page to continue.
Reload this page"
Reloading the page worked OK.