I upgraded my 2011 MBP to El Cap a few days ago but Safari was just grinding to a halt so I gave it a day but it didn't make any difference. I decided to wipe and go back to Lion. I'm back on Lion but Safari has the odd issue. I can't work out whether it's just because it's an old OS and some pages aren't optimised for it or what. Like for example, on the Twitter home page when I click on a tweet nothing happens. Previously the tweet would expand and I could see replies, etc. Also, when I go to someones Instagram page the pictures are just so blown up I can only see part of one pic before scrolling down and seeing a big part of another pic. I'm not sure whether it's a setting I need to change or I just need to upgrade to a newer OS?