I never said the XP-90C was a bad heatsink. I just sold a 939 system with a XP-90C/Panaflo M1A-BX that does very well.
There are more efficient heatsinks made today compared to the XP-90C. As hard as chas1723 wants to push his processor, he will need something more efficient than his present setup.
Putting a higher cfm fan on the XP-90C is a viable solution, but he will be sacrificing total system db.
I personally prefer death quiet PCs and that's what I build for myself and my customers. Using large, low RPM fans in the case, and installing the largest possible heatsink/fan combo on the processor allows you achieve a virtually silent PC even with a stout overclock.
Installing a 92mm fan in the 55-65cfm range on the XP-90C will make chas1723's PC noticeably louder. If he doesn't mind, then by all means, install the higher cfm fan.
I gave him that recommendation but I also gave him a quieter solution.
If the Ultra-120 will fit, I still stand by my recommendation.
It might be a moot point though if it won't fit on the Neo2 Platinum.
Anyway, have fun!