acceptance_helper.rb

require 'spec_helper'
require 'steak'
require 'capybara/rails'
require 'database_cleaner'
require 'akephalos'

DatabaseCleaner.strategy = :truncation
Capybara.default_selector = :css

class ActiveRecord::Base
  mattr_accessor :shared_connection
  @@shared_connection = nil

  def self.connection
    @@shared_connection || retrieve_connection
  end
end

# Forces all threads to share the same connection. This works on
# Capybara because it starts the web server in a thread.
ActiveRecord::Base.shared_connection = ActiveRecord::Base.connection

Spec::Runner.configure do |config|
  config.include Capybara
  config.use_transactional_fixtures = false

  config.before(:each) { DatabaseCleaner.start; }
  config.after(:each)  { DatabaseCleaner.clean; }

  config.before(:each) do
    account.update_attribute(:domain, "acceptance")
    Capybara.default_host = account.full_domain

    if options[:js]
      Capybara.app_host = "http://#{account.full_domain}:9887"
      Capybara.current_driver = :akephalos
    end
  end

  config.after(:each)  do
    Capybara.use_default_driver if options[:js]
    Capybara.reset_sessions!
  end

end

# Put your acceptance spec helpers inside /spec/acceptance/support
Dir["#{File.dirname(__FILE__)}/support/**/*.rb"].each { |f| require f }

Vou testar na minha suíte aqui mas você teve um ganho significativo?

Sim