Nominally these are to support higher end cards for things like CUDA and OpenCL. Interestingly, though, the official drivers contained in updates from Apple have evolved support for pretty much every nVidia card since 2010, and recently starting gaining support for the AMD 7xxx series. For example I run a hackintosh with a fully enabled GTX 470. In Snow Leopard days I had use the nVidia supplied drivers for their workstation cards, these days it Just Works.
Nominally these are to support higher end cards for things like CUDA and OpenCL. Interestingly, though, the official drivers contained in updates from Apple have evolved support for pretty much every nVidia card since 2010, and recently starting gaining support for the AMD 7xxx series. For example I run a hackintosh with a fully enabled GTX 470. In Snow Leopard days I had use the nVidia supplied drivers for their workstation cards, these days it Just Works.