Hi. I have an Intel MacBook. I doubled my RAM, to 2GB, and found that was quite helpful. I now also have almost all of the graphics turned way down, as I don't find much time to admire the textures. This, too, seems to make the game less choppy. What machine, and what gfx card (or lack thereof, as mine has an integrated GPU that shares memory with CPU)?
But before you go spend money, also, what kind of router/wireless/modem/connection do you have? Could it be either your internets or your wireless environment?
I use Airport, which was pretty fast as of last year, (to make up for the crappy gfx processing abilities), and it's almost seamless, but I am not really running any sort of process to monitor the performance. I also use a wireless mouse and keyboard as well as an external monitor, so pushing it with two antennas at once hasn't been a problem either, except for the heat issues (I recommend a cooling stand for this laptop).
Anyway, to sum up, idk it could be a few things, and someone more knowledgeable will probably come along soon and correct all of my misapprehensions. Good luck with it, and more info would be useful for any potentially helpful posters who happen along.