Well, I'm kinda having the same problem. But a little bit different.
For me the memory usage increased with Opera which added WhatsApp and Facebook Messenger into the browser.
It's not a biggie for me, I can live with it (I disabled/unchecked both anyway).

What bothers me is that with Opera 46.0.2597.32 (Windows 10 64-bit) Mixcloud doesn't work fine anymore ... mouse cursor with blue wheels starts to blink after is press "play" button. It doesn't matter do I have just 1 or lots of tabs opened, it keeps blinking even when the browser is minimized or is in the background or other tab is opened. After closing Opera, the blinking stops.
Opera task manager shows same time flashing GPU process ... see gif image below
https://media.giphy.com/media/3o7buaY0GuIUQzrn3i/source.gif

Same issue also with Google Maps

Sometimes it happens also with Soundcloud and IG, but only when lots of tabs opened and only when scrolling the page. Blinking stops after mouse click.
Twitter, FB and YT working fine.
With Vivaldi, Firefox, Edge no problems with Mixcloud showing up.

I tried without extensions, cleared history, cleaned profile folder, updated Flash player ... nothing helped.
Finally after hardware acceleration is enabled the problem with blinking mouse cursor seems to be gone.
But something tells me it ain't the right solution.

PS! Opera 46.0.2597.32 loads speed-dials a lot longer/slower than before.

Thank you @lando242 for your reply.
Deleting cookies, cleaning history, etc doesn't help.
However somehow viewing the page in a private window works ... so far so good.

But it ain't solution for the problem, all it started with the new Opera 33 browser.
A friend of mine have exactly same issue and he has no extensions installed in his O33 browser (its extension manager list is empty), so it may be not extension based issue.

Btw, it happens not only on Opera browsers ... also on Chrome browsers (google chrome black boxes).
And not only on browsers working on Windows based operating systems. From Opera for Android forum I found and discussion with similar issue
https://forums.opera.com/topic/12135/opera-33-beta-released

No, enabling/disabling hardware acceleration doesn't help.
Same effect with resetting flags to default ... still those annoying black boxes unfortunately.
Tried unsuccessfully with 2 different computers (Win7 Pro SP1, Opera 33.0.1990.115)

1 example

[](http://postimg.org/image/55if6daep/' target='_blank)

Thank you @l33t4opera

Is it possible to disable history synchronization?
It's question of privacy - believe or not but there're people who use work computers for non personal purposes but still want to keep their bookmarks synced.

Same issue here too with 2 different computers (Win 7 Pro SP1 and Win 7 Home Premium SP1)
Browser version 31.0.1889.174
Caches cleared, all extension disabeld, still black screen videos.

Seems that deactivating opera://flags/#experimental-start-page isn't available in Opera 31.0.1889.99 anymore.
Is there any other way to solve this (to get rid of those white spaces where names of pages are placed in Speed Dial)?