Why is this taking forever

Nature of the beast.

Wireless to wireless transfers generally occur at a bit less than half the full bandwidth for the channel. Half is for System 1 -> Wireless Access Point/Router and the other half is for Wireless Access Point/Router -> System 2

This rate still seems rather slow. How does your internet speed look like http://speedtest.net

EDIT: read this for more about transfer rate: http://forums.macrumors.com/showthread.php?t=458405

Do you have any old/legacy devices on your network?

B

 

Are the XP boxes by any chance on 802.11b/g?

B

 

So the whole network falls back to b/g. i.e. a max of 54 Mbit/s for g or 11 Mbit/s for b (careful if you are comparing Mbits to Mbytes too).

Unfortunately you can't expect 802.11n speeds if you aren't running a pure 802.11n network.

This may not be the main problem, but it certainly doesn't help.

B

 

True-ish, but:

My understanding of how the Time Capsule implements "simultaneous dual band" is that it has separate radios for the 2.4 GHz and 5 GHz bands. You can dedicate the 5 GHz for 802.11n and run b/g/n at 2.4 GHz simultaneously. Many other 802.11n routers are dual band, including other Airport and Time Capsules, but they have to pick one or the other.

B