You mean the recording system that came with FS?  I wouldn't bother using it.  FS's normal system stuff usually sucks, so go ahead and download FRAPS and use it.  Many people swear by it, although I will say I have never used it.

Fraps writes a AVI file. A 30 sec fullscreen AVI file can be 400 - 600 mb. You will also need this (free) http://virtualdub.sourceforge.net/  Virtualdub will compress that AVI down to a more manageable size. 600 mb avi fom fraps will compress to around 50 - 75 mb or so in Virtualdub. I then take that compressed file in your editing program of choice, ie Windows Movie Maker, Nero Vision, Sony Vegas to name a few, build your movie scenes and save that out into WMV or what ever formats works best. Ending file size using the 30 sec fraps file compress in vdub and exported in edit software for me is then around 8 - 10 mb.  Here is a link to a better explanation of how to do it.  http://www.grrr.co.za/index.php?option=com_content&view=article&id=62:tips-fraps...; Have fun!

Jim