This doesn't even matter on your internet connection, or CPU speed. If people with dial-up and school dell computers can get that low of a result, then it's not the speed of the computer or the internet, just the site itself.
I would venture a guess that a lot of the times has to do with how well the system is set up to do the search and how much traffic is on that system's server at the time. But looks like Google's got a setup that can handle the load quite well.