Simple low-light test, room was lit by a single overhead compact fluorescent. DVX100B was full wide angle, lens wide open, maximum 18dB of gain, and running in interlaced mode (which gains an extra stop of sensitivity).
AC90 was zoomed in slightly to match the field of view of the DVX100B. Also running wide open, maximum 30dB of gain, in 1080/60p mode.
Neither camera was white-balanced before the test (sorry 'bout that).