FWIW the texturesize calculation is not as off as people seem to think.
Many video drivers truncate 32 bit textures to 16 bit. Most allow you
to turn this feature off, but many have it on by default. When N4 tries
to determine the texture size for a 32 bit mode, if you have this
feature on, it will appear to find more memory than there really is.
The "wrong" number that it ends up with is actually correct as long as
you leave that feature turned on. If you turn it off, you will have to
either recalculate the number or just re-run the setup. On my system at
least, N4 has always ended up with a texture size that made sense for
the video mode and the driver tweaks that I was using, I have never had
to change it.
