@pow1 ok, thx for checking. I have a lot of bookmarks on the bookmarks bar (in bookmarks bar folders) and favicons are also not loading, but bookmarks are clickable. Browser is also fully responsive during this time.
*Maybe you can try installing 89 portable version (usb installation option selected in installer). Here the portable version opens speed dial instantly (but there are only few default tiles, of course).
So maybe there's some profile issue in my case after update. But speed dial is fast again if I revert back to 78 version.