I find the game change speed to work well for me. You must use the + and - keys above the letters on your keyboard (not the ones on the keypad--the spot that has 0-9 on it for use like a calculator).
If there are too many ships in the game the high speed is not as fast but its still quicker than, say, normal.
I think you can go from 1/4 speed to a max of 10x. Its nice because I can speed things up if nothing is really going on and I just slow it down real fast when combat happens.