Facebook not only takes a big chunk of your iPhone's storage memory due to your Timeline, Photos and Videos, but the Facebook App itself, slows down your iPhone drastically due to the extensive RAM requirement.
I found an AWESOME FIX, DELETE your iOS Facebook App altogether, then use Safari and Log in to your Facebook account, and instead of creating a not so convenient bookmark, you will create a link by pressing the Safari "send" icon, and choosing the +"Add to Home Page" option, which will create the recognizable "Facebook Icon" link, as if it were your Facbook app. I did noticed my iPhone a bit faster, as well as freeing up almost a gig of data.