You'll probably notice that the 404 pages across most Google properties is the same. For example:<p><a href="http://images.google.com/mapss" rel="nofollow">http://images.google.com/mapss</a><p>And you might also notice that no matter what subdomain you hit, the path is all that seems to matter:<p><a href="http://images.google.com/maps" rel="nofollow">http://images.google.com/maps</a>
<a href="http://maps.google.com/images" rel="nofollow">http://maps.google.com/images</a><p>It would be logical to conclude that there's some server you're hitting before you get to the service specific backend, and that maybe that is the reason the 404 pages come back faster.