The following Command line switches are currently known to be helpful in troubleshooting the game. See this thread for more detailed info on some of the command line switches. The modding community has also put together this list.
A command line switch is added to your HW2 Shortcut by right clicking on the game's shortcut, going to properties, and adding it (with a space) to the end of the Target Line on the Shortcut Tab.
"C:\program files\Sierra\Homeworld2\bin\release\Homeworld2.exe" -nosound
-nosound - Runs the game without sound. Useful if trying to rule out sound problems.
-w xxxx -h xxxx - Sets the resolution of the game. Useful to try and work around the limited resolutions in the game's menu. Can be used to stretch the game across multiple monitors. Note: the game is optimized for 4x3 display ratio.
-windowed - Runs the game in a window, must specify resolution. ex: -windowed -w 640 -h 480
-refresh xx - Forces the game to run at a specified refresh rate.
-noVBO - disables support in game for Vertex Buffer Objects. Useful for troubleshooting geometry related glitches. See this thread for more detailed info.
-noDisplayLists - disables display lists. Useful for troubleshooting geometry related glitches. See this thread for more detailed info.
-nopbuffer - disables pixel buffer support. "If you disable pbuffer support you will not get any render to texture effects (shadows and the high quality hyperspace effect-you'll be able to see into your ship like HW1). " See this thread for more detailed info.
-nomovies Skips ALL movies including the opening ones.