Comment by TinkersW

On the CPU side, yes 64 bits is a good idea, but when transferring to the GPU you simply make the camera location 0,0,0, and transform everything relative to it, thus you can easily use 32 bit float and have no z-fighting or any other precision related issues(a logarithmic depth buffer also helps).

Regarding 64 bit double vs 64 bit fixed width, I don't think there is a really good reason to bother with fixed width, it adds more instructions, and will require a custom debug visualizer to inspect the values.

Bit shifts, at least in SSE/AVX2 etc, are only able to run on a single port, so they actually aren't such a great idea(not sure about scalar, I don't bother to optimize scalar code in this way).