Eclipse is very slow when updating
Eclipse can be very slow when running "Check for Updates" or "Install new Software". This is an old issue with Eclipse and it seems to be caused by slow or outdated Eclipse mirrors. This becomes even more frustrating when you have to use Eclipse behind a proxy.
The good news is that you can disable the mirror checking behavior. Open the "Install New Software" dialog and uncheck the "Contact all update sites" option. Now Eclipse will be sensibly faster.
You can also modify eclipse.ini to include the -Declipse.p2.mirrors=false. It has the same effect.