I usually work with relatively small assemblies (10 parts max) and more often that it's only individual parts. but I've been working on a project with one of the designers and today in putting all the pieced together Solidworks started to slow way down. The assembly we are working on currently has only about 320 parts in it (some in sub assemblies) but behavior, such as trying to move mechanism pieces, has become almost impossible. I open the task manager and SW's memory usage is about 225,000K which is less than Firefox some times. The file I'm working on does have a lot of fasteners but I have been keeping them hidden to speed the graphics motion. Where SW has been very stable for me, with this assembly it is now freezing when I try adding certain mates. This machine is an Intel core i7 920 (2.66ghz) based machine with 6gb ram running windows 7 (64bit) so I would expect better performance. Is there a primer or tips on tweaking performance somewhere or can someone point me in the direction of a previous discussion on this subject? I would refer this to the IT department if we still had one after the last round of layoffs. As the assemblies sit now I can't move any of the components without huge delays and parts that jump to new positions seconds after I move the mouse. Could this be a graphics card issue?