I cant totally confirm or backup this ... but they claim that the 2nd gen M-dies (placed in 24GB sticks) are more easy on the imc part.
At the end , you will always achieve what your imc can give you.
From personal experience with random , low bin ram kits , both the A-die and the M-die got at the same top speed and similar settings , just my M-dies used a little bit less voltage.