Liquid CPU airflow

[rossandersonuk]

so im getting this http://eu.coolermaster.com/en/cooling/cpu-liquid-cooling/seidon-120v-v3-plus/ and im wondering i should replace the stock fans with thease i have laying around http://www.corsair.com/en-gb/air-series-af120-led-blue-quiet-edition-high-airflow-120mm-fan

it seems the airflow is better with the fans on the cooler being 36 ~ 86 CFM ± 10% and the corsair being 52.19 CFM.
What i dont understand is why there are 2 numbers and what the 10% means ?!
hope someone can help thanks

 

[GhislainG]

The Corsair case fan doesn't provide enough pressure or airflow. The fan on the cooler provides up to 86 CFM at 2.87 mmH2O; the Corsair fan provides up to 52 CFM at a much lower .75 mmH20. ±10% means that the specifications can vary by up to 10% either way.

 

[Paperdoc]

I agree with all the above. Just to add, the reason there are two airflow ratings is that these are for two different fan speeds: the lowest and highest speeds they should run.

Reading and understanding fan airflow and pressure specs is tricky, and I think I've found what they mean. The two specs given actually are HALF the info. The max airflow given is only for when the fan experiences NO back-pressure to reduce its airflow. The max pressure spec is the back-pressure at which the airflow is reduced to almost nothing. So for that fan supplied with the rad, at maximum speed it will deliver 86 CFM against no back-pressure, and no airflow against a back-pressure of 2.87 mm water. If you sketch your own graph of airflow versus back-pressure between these two points, a typical fan's "curve" will be roughly a straight line between those points. Now for comparison, draw another line for the Corsair unit you linked. Max flow (no back-pressure) 52 CFM, no airflow at back-pressure 0.75 mm water. Now, we don't know what back-pressure the rad in that liquid cooler system offers, but you can be sure that at any reasonable value (say, 1.0 to 1.5 mm water), the fan supplied with it will do MUCH better that the Corsair unit.

Hint: if you read the Corsair specs for that fan carefully, you will see its design is optimized for best air flow, and that means (not stated very clearly) under conditions of minimal back-pressure such as a case fan will experience. The make a different line of fans for "high pressure" use on radiators and heat-sinks.

 

[n0ns3ns3]

in addition to very comprehensive answer above, the simple answer is NO you shouldn't until those fans die - will take some time.