To save Michael a job (I hope) , MoI is 32 bit. However, the only difference between a 32 bit app and a 64 bit app is memory addressing, not the actual processor performance. If you run a 32 bit app like MoI on a 64 bit system, MoI should be able to address 4GB of memory.

As for OpenGL, Moi doesn't use it. It uses DirectX.