Comment 4 for bug 651482

 So the first point is that this only happens when you have _large_ amounts of
packages, so if you don't have @everything ... things are much better.

 If the timings suggest that it is doing more work per. pkg as the pkg count
gets higher, then you could try (I would run a yum update -y too, after this
finishes):

http://people.redhat.com/jantill/yum/commands/yum-iter-update.py

...or something like it (it basically tries to install the updates one at a
time), and a supported core feature to do something like that might be making
it's way upstream for later release.

 But my quick numbers suggested that wasn't the case.