Someone

import time

import gtk

window = gtk.gdk.screen_get_default().get_root_window()
width, height = window.get_size()

t = time.time()

pixmap = gtk.gdk.Pixmap(window, width, height)
pixmap.draw_drawable(window.new_gc(), window, 0, 0, 0, 0, width, height)


print time.time() - t