This is just because your browser is trying to render a load of content, not a lot we can do about that - it was the case before the ugprade too.Loading a site with a lot of embeds uses a lot of CPU, and also takes awhile to load, try here: https://forums.overclockers.co.uk/threads/youtube-video-thread.17937182/page-227
This is probably made worse by me having 100posts/page