Hi there,
Not using the Coolermaster but I do have one of the biggest Air Coolers on the Market and having just double checked the important measurements I believe that you should be OK.
As you can see from this picture, My cooler sits over all of the Memory slots on my Mobo and the Coolermaster N520 is actually quite a bit smaller.
And the measurements for both coolers:
The deciding factor whether the cooler will actually fit will be the overall height of your RAM modules but I think you should be OK there too.