The radiator seems to be the same size. The Hyper ML240L does not support the am4 socket and the Masterliquid, which is why the ML should be newer and therefore probably also equipped with contemporary RGB. Since the radiator is the same size and the specs of the fans/airflow are practically identical, the cooling performance should be identical.
Yes, I even had an i9 9900k and an i7 8700k cooled for a short time. For an all-in-one cooling system, it is top for the price! Only the fans are too loud for me...
So I looked at the housing again. It's pretty sure it won't fit at the top. The bottom won't work. If it does, then only at the front. But as I said, measure first and then buy an AIO.
Hello FuriousJan
Unfortunately the Coolermaster ML 240L RGB does not fit in the P400a rgb. It only fits 2× 120mm fans and no radiator. http://www.phanteks.com/Eclipse-P400A.html
I have a Coolermaster mb520 RGB and the water cooler fits exactly.