Firefox takes over 30 seconds to load a tab that I've already opened and seen before. I mean tabs that have already displayed some content, I switch to a tab, then go back to the tab I was previously on, and it takes over 30 seconds to load, sometimes over 3 minutes. This is making firefox unusable. And because it doesn't happen all the time, it's not very reproducible for me, but it happens often. Is there a way to fix this?