- Jan 23, 2013
- 34
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- 10,530
Hey all,
I just picked up a new Fractal R4 case from newegg and am planning out the airflow. The many articles I've read seem to indicate that negative case pressure is slightly better for cooling then positive. For the record I'm running a 3570k oc'd to 4.4 ( though it clocks down when idle ) and a gtx 680 oc'd by about 140mhz (didn't touch the voltage).
I'm assuming that airflow is restricted about 50% by the filters. As such, I've planned for 3 intakes (1x66 cfm R2 fractal design and 2x56 cfm bitfenix located at the front 2 positions and 1 on the bottom of the case ) bringing my total intake to 178cfm. Assuming that airflow is restricted by half this is ~89 cfm total entering the case. For exhaust I thought I'd run two at the back and top back of the case, at 66cfm and 56 cfm respectively - bringing my total exhaust to 122cfm ( no filters for exhaust obviously ).
The other option is to run three intakes in the positions mentioned but only one exhaust at the rear of the case. Where this would normally make for positive case pressure I've reasoned that if I restrict ( with fan Xpert or the like ) the rpm of the intakes to peak at 50%, I wouldn't get an intake of more then ~45Cfm ( 178cfm / 2 ( filters ) = 89 x .50 = 44.5 cfm ). If I also set the one rear exhaust (66 cfm ) to never power down beyond 70 % ( 66 / 45 = 68cfm ) then I would still have a negative case pressure situation, albeit with less total airflow through the case - while maximizing the area's of air intake by having 3 fan intake positions.
Is my reasoning sound here? or am I way off.
Thanks for the input guys! ( and gal )
I just picked up a new Fractal R4 case from newegg and am planning out the airflow. The many articles I've read seem to indicate that negative case pressure is slightly better for cooling then positive. For the record I'm running a 3570k oc'd to 4.4 ( though it clocks down when idle ) and a gtx 680 oc'd by about 140mhz (didn't touch the voltage).
I'm assuming that airflow is restricted about 50% by the filters. As such, I've planned for 3 intakes (1x66 cfm R2 fractal design and 2x56 cfm bitfenix located at the front 2 positions and 1 on the bottom of the case ) bringing my total intake to 178cfm. Assuming that airflow is restricted by half this is ~89 cfm total entering the case. For exhaust I thought I'd run two at the back and top back of the case, at 66cfm and 56 cfm respectively - bringing my total exhaust to 122cfm ( no filters for exhaust obviously ).
The other option is to run three intakes in the positions mentioned but only one exhaust at the rear of the case. Where this would normally make for positive case pressure I've reasoned that if I restrict ( with fan Xpert or the like ) the rpm of the intakes to peak at 50%, I wouldn't get an intake of more then ~45Cfm ( 178cfm / 2 ( filters ) = 89 x .50 = 44.5 cfm ). If I also set the one rear exhaust (66 cfm ) to never power down beyond 70 % ( 66 / 45 = 68cfm ) then I would still have a negative case pressure situation, albeit with less total airflow through the case - while maximizing the area's of air intake by having 3 fan intake positions.
Is my reasoning sound here? or am I way off.
Thanks for the input guys! ( and gal )
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