qkrzazzang :
So I just found out that 750D is not compatible with CEB Form factor (P9X79-E WS). So I took a look at Rampage 4 Black Edition, which is E-ATX. However, I'm not so sure about the difference between these two. What are the differences? Which one is better?
The P9X79 series motherboards are aimed towards mainstream and professional users. They have lots of bells and whistles and are built to Asus' standard quality levels.
The Rampage IV series motherboards are part of Asus Republic of Gamers enthusiast lineup. They are aimed towards tweakers and enthusiasts. Bells and whistles are limited but the components are of the highest quality and the boards are built to take a beating. The high end Rampage IV boards (at least the Extreme, which I have) are equipped with voltage test points, extremely accurate temperature sensors which work well below freezing, high quality cooling, and external overclocking features which allow a PC to be tweaked remotely.