When you use yum to perform updates in Fedora, it goes and gets the updates from any of a number of mirror sites that Fedora uses to host the updates. Often the updates are large and downloading the updates can take a while. There's a package called yum-fastestmirror that can help speed up this process. It tests the various mirrors and keeps track of which ones offer the fastest downloads. So when yum needs to download packages as part of an update, it will then favor the fastest mirrors rather than just picking one from random as it normally does.

All you need to do to get this speed increase is install the yum-fastestmirror package. Run this command from the command line,

yum install yum-fastestmirror

That's all there is to it. After that it takes care of itself automatically and you get faster updates in Fedora.