I'm pretty sure this has been showing in the WordPress admin Dashboard until very recently. I just installed AddThis and it also has a dashboard widget for the admin dashboard. I got the impression it may have taken the page-speed widget's place. I have tried unchecking and rechecking the option on both. There's heaps of space with 3 columns. Everything is up to date. I saw a similar post from a month back that mentioned it being in the widget dashboard, but I'm not sure I followed the explanation. thanks.