trouble with slow rubygems

Hi there,
I'm having a lot of trouble trying to install any gems in ubuntu.
Every time I try I get:
Bulk updating Gem source index for: http://gems.rubyforge.org/
and then that hangs forever. More often than not I get a server
timeout on my SSH session before anything changes - that timeout is
currently set to 2 hours.

I don't understand why gem needs to Bulk update *every* time I try to
install anything with it.

I also tried:
gem install rails --source http://gems.rubyonrails.org
and got:
Bulk updating Gem source index for: http://gems.rubyonrails.org/
Bulk updating Gem source index for: http://gems.rubyonrails.org/
and then hanging.

I've never had this problem before with gem and I can't work out what
might be wrong.
Does anyone know what could be causing it to take so long?

thanks
dorian

This may work for you too http://ruby.tie-rack.org/58/speeding-up-gem-on-os-x-leopard/

I've seen hangs due to memory issues. The bulk update is very hungry.
Once the bulk update runs to completion once, things get much faster.