Noctua NH-U14S is it worth...
- Thread starter bigmac121
- Start date
was thinking the same. I thought push push would have lowered it more.
Maybe for a double tower, but for a single tower, one fan blowing is already shedding the heat out of the tower to the ambient air. The top half of mine doesn't even get warm with the CPU running at full tilt (4770K at 4.7 Ghz). You're probably better off finding a place to use the second fan in your case. You want to stop heat buildup in the case ie get the hot air out of the case so the CPU cooler works better. The lower the temp in the case, the easier it is for cooler to shed heat with the help of the fan.
Thanks. I have 2 intakes at the bottom. I have 2 intakes at the front. Rear exhasut and top. Also H90 exhasut at the top
Simple airflow about fans; stacking fans does not increase their airflow rating, but does increase their static pressure rating. But they need to be either rotating in opposite directions or have an airflow straightener between them to get a pressure increase. Reason is fans tend to spin the airflow so 2nd fan turning same direction is just flowing air with no increase. The reason a push / pull improves flow on a cooler or radiator is because of the pressure rating increase.
How Airflow and Static Pressure Specifications relate to real world use.
Airflow specification is the maximum airflow of a fan with no resistance to the airflow ..
Not a real world use of our fans.
But we use the fan in a case with a grill (restricting airflow) and often a filter (also restricting airflow) and often blowing into a HDD cage (still more restriction to airflow).
End result is that the fan specified airflow is more than twice what is actually flowing .. in fact often even more.
Static pressure rating is the pressure level when air stops flowing .
Again, not a real world use of our fans.
The reality is that if we have 2 fans, one with a higher airflow and lower static pressure rating and the other with lower airflow and higher static pressure rating .. but in almost every case (no pun) the lower airflow / higher static pressure rated fan will flow more air than the higher airflow / lower static pressure rated fan will
Let us look at fan A with 70cfm & 0.8mm H2O rating compared to fan B with 50cfm and 2.0mm H2O rating.
Now let us assume the grill, filter, HDD cage, cables etc. create a pressure level of 0.35mm H2O .. half of fan A's rating .. which drops the cfm by about 60-70% giving us 21 -28cfm of airflow. But for fan B the 0.35mm H2O resistance is dropping the airflow by 20-30% leaving us with 35 - 40cfm of airflow.
Fans A and B with 0.35mm H2O resistance
- Fan A 70cfm & 0.8mm H2O fan is flowing 21-28cfm.
- Fan B 50cfm & 2.0mm H2O fan is flowing 35-40cfm.
But what if the grill, filter, HDD cage, cables, etc create 0.8mm H2O? This is the static pressure rating of fan A .. so now it is flowing no air.. But for fan B the 0.8mm H2O is less than have it's static pressure rating and iy will still be flowing about half of it's rating leaving us with about 25cfm airflow.
Fans A and B with 0.8mm H2O resistance
- Fan A 70cfm & 0.8mm H2O fan is flowing 0 cfm.
- Fan B 50cfm & 2.0mm H2O fan is flowing 25cfm.
These are estimated resistance and airflow to resistance to give an example. Hopefully it helps you understand how static pressure and airflow relate to each other
In most cases a fan with a real static pressure rating of about 1.5mm H2O will do a good job of moving air.