What version of the game?

how large of a map and how many players are you playing against

Okay I was assuming you made a custom map with the random map generator, large maps are small in comparison to maps made with that. 256x256 lol large map is large that translates into 16x16 map

There's a 1.2 being beta-tested atm to weed out as many memory issues as possible. A new build just went live today if you want to try that (select "Show Pre-release Versions" in Impulse).

Please note that you need to have a constant internet connection when using beta builds (wil not work offline). This reliance is taken out for the official builds.

Hope the new version helps you get further into a game