I think another important point is the system youre running!I my case its Windows NT 4 with SP6.The great advantage is the possibilty to control the systems parameters like memory-adressing,etc.If youre running Win 98 Se,Win 95 or Win Me, you might miss some of that features. I didnt clearly found out the limits of my computer yet,but I startet with an 6 year old 166 MHZ Pentium; what forced my to look at resourses of my PC. My scenes are getting bigger and bigger but I still try to reduce (I hate non realtime-previews and render- ing-times over 47 hours !). So reduce polys whereever you can ! rollmops :-)

http://www.fredivoss.de 

...yippi ah yeah or something like that...