No star for testing, so just take a shot with terrestial targets. The color shot is obtained by my DBK 21AF04.AS which has a 1/4" color CCD, zero gain is used at 2s each, the black white shot is acquired by my DMK 31AF03.AS which has a 1/3" monochromatic CCD, zero gain is used at 1s each. Seems like the monochromatic chip has twice the sensitivity of the color chip. Both at f/1.2, i.e. wide open.
With a large chip, the monochromatic one covers more area. No UV/IR block is used.