The dust on the galaxy map can be removed (and thus your performance improved) by simply setting the following values in the defines to zero, like so:
It helped me to run the galaxy map a bit smoother, I hope it helps someone else as well.
Code:
GALAXY_DUST_SIZE = 0.0,
GALAXY_DUST_SIZE_EXTRA = 0.0,
GALAXY_DUST_ROTATION_SPEED = 0.0,
GALAXY_NEBULA_DUST_SIZE = 10.0,
GALAXY_NEBULA_DUST_SIZE_EXTRA = 25.0,
GALAXY_NEBULA_DUST_ROTATION_SPEED = 0.0,
It helped me to run the galaxy map a bit smoother, I hope it helps someone else as well.