I have done some research into this issue, and the analysis of vmmap dumps on affected systems indicates that both the application itself, and the graphics driver, are allocating space for texturesâ€â€which must compete to fit in the same 32-bit address space. The result is that between the app itself, the graphics drivers, and various system frameworks, using full resolution textures can leave you right on the edge of memory exhaustion at the main menu! The short term workaround is to lower your texture settings as low as possible, in order to leave as much overhead as possible. The long term fix is to either find a way to greatly manage texture memory more efficiently on OS X, or to move to a 64-bit build. Both of these are non-trivial for KSP from what I gather. Unfortunately, if this is true, I imagine that a fix for 1.0 couldn't be fit into a schedule already made tight by developing so many new features, even if they wanted to fix the problem.. Note that the motivation for this theory (in summary) is that by using mmap, I could see both the application's own MALLOC region, and the the IOKit region, scale by the same amount as I increased texture resolution. Other memory regions remained relatively unchanged, and varying other parameters left all memory regions relatively unchanged. I combined this with some Apple documentation on its OpenGL pipeline that describes how the OpenGL drivers can keep their own copy of the texturesâ€â€outside of application the application's heapâ€â€to load to VRAM as is necessary, and that your application has no direct control of this memory management.