ähhh guys you know that these speed test are pretty much a waste of time?!

you expect that the route from the N900 to the server (which shows you the result) is... let's say comparable with a road that is turning into a highway (the bigger back bone of the ISP) and that there is no stop and go traffic on that street.
but that is wrong. first of all you don't necessarily use the shortest way to reach the server. then you don't know how the server is connected to the network (maybe it is a single line road).
and then there is the friendly police man on the street that say "oh sorry lorries has to queue in just one line, while busses and cars with more then one person in it can use all the other lines (priority of different packages)... just do say some of the things that could limit the throughput of your connection.

packages for these kind of speed test are not always the high priority packages for an ISP. similar to P2P traffic, it will be slowed down by some of them. not necessary your ISP but one of the companies between you and the server.

then you also have the limitation of your ISP/Phone company. maybe you are in an area with a lot of customers, so they tell you that you get a highly desirable HSUPA/HSDPA or just UMTS connection. your phone shows you that you get a 3.5g connection. but somewhere behind the link (phone <-> base station) your traffic is queued, just to allow everyone in your cell to browse the web.

there are so many things that will influence with these speed tests... you can't count them all.