Shared Start Page enabling helped, thanks.
Version is 65.0.3467.48 64-bit.
I have about of 50 links on start page.

@burnout426
I've downloaded portable opera 65 and got the same problem even after I removed all links using start page settings.
It become a bit faster if hide search field and express-panel.

But it's really fast with Shared Start Page feature enabled only

I see that Opera takes about of 40% of CPU permanently(created a thread about miner before, but it doesn't look like miner), seems got some details:

Task manager says the browser itself take it, not specific page.

Any ideas how can it be fixed?

I see that Opera takes about of 40% of CPU permanently(created a thread about miner before, but it doesn't look like miner), seems got some details:

Task manager says the browser itself take it, not specific page.

Any ideas how can it be fixed?

@leocg Checked that setting - it's disabled. But really looks like it's enabled for part of sites somehow

I've reset the opera settings(using update&restore menu) and also updated to 68.
And now I don't see different sites settings(saved in cookies?) are restored after relaunching the opera.
E.g. I have discord tab and need to login there each time I'm reopening opera.

Just an update - problem resolved after I reset the Opera settings

@leocg
As I said, "Browser" takes the CPU

Sorry for russian - "Браузер" means "Browser":)
So the problem not in some "miner" opened pages

Appreciate for any ideas to get details about actual cpu loader.
I tried to switch off all extenstion, btw.

The problem - opera takes about of 150% of CPU(1,5 cores) even it is minimized.
It is not depend on the site I opened, and it's not reproducible if no sites opened(so just one tab - express page).
The task manager shows that Browser using it(so it's not specific page, the problem is in Opera)
Any way to get the reason of that problem?

Checked the system with Kaspersky and Malwarebytes - nothing.

@burnout426
I've downloaded portable opera 65 and got the same problem even after I removed all links using start page settings.
It become a bit faster if hide search field and express-panel.

But it's really fast with Shared Start Page feature enabled only

Shared Start Page enabling helped, thanks.
Version is 65.0.3467.48 64-bit.
I have about of 50 links on start page.

This problems have been reproducible since 65 or 64 version.
So when I open new page(even express-panel or version-page) it takes almost 100% cpu(not sure if it's related) and takes a few seconds.
Gif as example:

So how can I switch off flash for that site?

You can't. You will have to manually turn Flash off.
You can try contacting the site and ask them why they don't offer html5 by default.

Ok, is that possible to manually switch flash off for only one site? Are there any plugins for it?
The bug on that task has two months age, so I don't think it will be fixed soon.