Hi torsten, if you have a heavy model then under Options > View > "Meshing parameters", try setting "Mesh angle" to a looser angle like 20 degrees and then uncheck "Add detail to inflections". That will make for a somewhat rougher looking shaded surface display but also greatly decrease the amount of triangle data that is sent to the card which can speed things up a lot.

re: graphics card recommendation, I'm not really up to date on what's current. On Windows though MoI uses Direct3D and not OpenGL and so doesn't really need a Quadro, the regular gaming card line should be fine but if you're running other apps that use OpenGL you may still need a Quadro since their OpenGL support is intentionally crippled on their gaming line, at least that's how it used to be.

First though check if tweaking those display settings gives you a noticeable boost or not.

- Michael