First thing is to find out what case you are using for this build. Only way flat coolers work is if is case has a vent directly over CPU for either supplying cooler with cool air or exhausting cooler heated air. If this is your sig rig, case has 180mm CPU clearance and is designed for front to back airflow, not side to motherboard. This means a small tower cooler will likely receive cooler air into cooler becaues it's pushing air through cooler toward rear exhaust venting. Flat cooler with fan pushing air down into cooler air hits motherboard turning out, hit's RAM, GPU, etc turning up along side of cooler and fan where it is then drawn back into cooler fan. End result is 8-12c higher temp air .. which translates into same 8-10c higher CPU temps. Turning flat cooler fan over so it's pulling from motherboard through cooler helps, but there is still not separation of cooler's heated exhaut and case's cool intake airflow.
Phanteks Owners Club Ways to Better Cooling
i7 980 @ 3.55GHz =PH-TC14PE w/2x TY-143 fans =Crucial Ballistix 3x4GB =GA-X58A-UD5 =ASUS GTX580 DirectCU II =Enermax Modu84+ =Define R2 w/3x TY-140 case intake fans; all PWM controlled by CPU fan socketPhanteks Enthoo Primo MoBo Rampage III Extreme CPUi7 980X
@ 4.0GHz =R1 Ultimate
w/2x TY-143 fans =Dominator GT 6x2GB
=Rampage III Extreme
=ASUS GTX580 DirectCU II
=Enthoo Primo w/ custom castor base