Glad you found something that works for you. 8.1, as a beta, has some issues. I fixed the mail thing, but uninstalling and reinstalling the mail app. Some apps open much fast with 8.1, some seem to be a bit slow. If seen the same behavior on pretty much all ARM based tablets. The iPad2 I used to have was the same - slow to launch compared to a full-powered desktop, but once open, everything was smooth. Most of my apps open in just a few seconds though - it hasn't been an issue for me, but it seems to depend on the app.