It's the "flare" on the side(s) that gives you the extra space.
It gives you clearance for big coolers on the fan side and space for cable management on the other side.
I'm running two 140mm fans on the side on my 400R and there is more than enough space for my 212+
Thank you! Confirming assurance is always good.
I was going to get the 400R but then the white 500R came up. Didn't want white but liked the case so it's now on the way along with everything else but the CPU. The most costly so put it off til last.