June 07, 2012, 12:58:41 pm
Hi palmy100, the most important factors are the graphics card, the Windows version and the system memory (in that order).
The CPU is not used much - it's mainly for compressing frames after they have been rendered.
The 32-bit version of Windows is unable to allocate more than 3.5gb ram to each application, regardless of how much system memory you have. For that reason, it is highly recommended that you use Windows 64-bit (Windows 7 is really worth the upgrade by the way). 4gb of system ram is on the low side, but it really depends on what kind of scenes you're planning on making.
If you do decide to upgrade to a GTX 670 card, make sure that you get a decent power supply. If it is unable to supply enough power you will experience unexpected behaviour such as warped polygons, crashes etc.