I have an install that has 3.4GB of mods just loaded to the space center scene. That's the razor's edge of a mem crash right there. In the past, someone had the bright idea of forcing KSP to run under DirectX11 instead of DX9. Some people tried and discovered it delivers massive memory savings. Some people also reported violent instability within their game when using this. What kind of memory savings are we talking about? Forcing KSP to use DirectX11 causes a 40% reduction in memory usage.