pip install --exists-action=w -r requirements.txt is very very slow through virtual box. Any suggests of how to diagnose and fix? Would seeing the VagrantFile be useful?

VirtualBox 4.2.12 (can't upgrade to .14 as it doesn't work.)

Vagrant 1.0.7

Host machine: ProductName: Mac OS X ProductVersion: 10.7.5 BuildVersion: 11G63b

VagrantFile contains:

Vagrant::Config.run do |config|
  config.vm.box = "precise64"
  config.vm.customize ["modifyvm", :id, "--memory", 2048]

  config.vm.box_url = "http://files.vagrantup.com/precise64.box"

  config.vm.network :hostonly, "33.33.33.21"

  config.vm.forward_port 5000, 5000
  config.vm.forward_port 5555, 5555

  config.vm.share_folder "v-root", "/vagrant", "./"

  Vagrant::Config.run do |config|
    config.vm.provision :shell, :inline => "VENV=/usr/local/venv bash /vagrant/setup_env.sh"
  end
end

Normal download speed is only about 5 times slower at 0.8 Mb per second versus > 4 MB per second (as judged by curling a 50 Mb file from S3). But pip install is taking about 20 times longer from Mac (i.e. about 40 minutes) versus 2.