FA lags horribly with 5 or more players on GPG

Some friends and I have been trying to get some multiplayer games going over GPGNet. We all have the latest patch, and we've all played several 4 player games with each other (different combinations of players) without any slowdowns at all.
No matter what we try though, or who that fifth player is, whenever we attempt 5 or 6 players, the game is horribly laggy, to the point of being unplayable.
What is magical about that fifth player? Why can four player games run so smoothly, but adding a fifth just kicks the speed in the jimmy? It doesn't appear to matter which of us drops out either, but as soon as one players drops in a 5 player attempt, the game speeds right up. We have no problems whatsoever the few times we've gotten together for LAN games (6-8 players no problem), but GPG seems to choke on 5 or more players. We've also tried different people hosting (better upload speed, different maps, sizes, etc).
Any ideas?|||This is not really a 'problem' on how many players there are in the game, but rather a hardware issue.
It sounds to me that one of your players connection or hardware simply cant handle more than four players. You can see the current game statistics by typing 'ren_shownetworkstats' in the console. This will reveal who's hardware is lagging the game down, or who's connection is spiking up that causes the lag.|||I had an interesting situation in a recent LAN party of FA with 5 players. 3 were connected via ethernet cable, and 2 were connected wirelessly. One of the two that was connected wirelessly had a very good computer, but suffered terribly jerky and laggy controls. A check of his sim speed, even with lots of units, however, showed it to be quite high. No one else was experiencing any slowdown, just him. When he disconnected wirelessly and connected via an ethernet cable, his problems went away and it was super smooth. The other computer that was connected wirelessly did not have this same issue, even though it was a slower computer.
Could it be a problem with multiple computers trying to connect to a router wirelessly?|||Falcrack