best practice when building

Hi everyone

Hoping for some general advice, I've finally started buiding my own models rather than just downloading other peoples' and am potentially running into a size issue.

My first big project is recreating in much better detail a spaceship I built originally in Photoshop and After Effects, (I know - now you underatand my desire for C4D :))

I've been building using primatives and am up to 500 objects and nearly 200,000 polygons and C4D has become sluggish. I've used booles to recess windows and to create radar dishes etc... and there's a lot of girders.

Have I just been overly complicated for my 1.5Gb of RAM? or are there polygon reduction tools I should be using?