Quote Originally Posted by ben805
Asus do not recommend the optional heatpipe fan unless you're on WC or Phase change, I do not think you can fit it on if you're using big cpu heatsink like XP120 or Big Typhoon anyway. As long as your case has sufficient air-flow you shouldn't need it
On my board the backside of the XP-120 overhangs the heatsink next to the I/O ports.