Xcode updating is extremely slow

Strangely enough, the fix for me was downloading the .xip file in Safari. It seems that the download was capped to 100KB/s on Google Chrome, using Safari there seemed to be no network throttle.

You can always download the dmg for new or earlier versions of Xcode (or any other developer tool for that matter) from this link provided by Apple for iOS and Mac developers.

I had the same issue downloading Xcode 7.2. The download was drastically slow compared to my internet download speed. Try this fix it worked for me:

Go to the app store/ Updates and pause the download

Go to the app store/ Purchased and log in if you are not already logged in

Restart the download

I noticed a huge increase in the download speed from 1d to 1h. Maybe it has to do with apple finding the nearest server according to your account location or some routing magic.