Need a opinion on fans

[lavonthurston77]

LL120 RGB 120mm Dual Light Loop White RGB LED PWM Fan has a Static Pressure 3.0 mm-H2O and Fan Airflow 63 CFM which seems to me to be the best rgb fan for radiator and case base on specs, need a opinion

[DevBiker]

Well, those specs are at max RPM, too. That's the thing - they have a higher max RPM than the regular LL fans. At the same RPM, they have the same specs as the non-white LL fans.

ML fans will have the best static pressure and CFM at lower RPMs. So unless you are running them at full speed all the time, the specs really aren't helpful.

That said, the differences in the end result is actually pretty minimal.

[c-attack]

No, the ML series is best of the Corsair fans for radiators. You are looking for a 7 blade fan (versus 9-11) with wide, flat blades. The LL, QL, HD fans are all general purpose design with medium blades, medium rake, etc. That doesn't mean they are not effective, but if you are chasing 2C of coolant temperature it may matter. The smaller your radiator (120mm) the more fan choice matters. As you increase down the line to 360, 480, etc. it matters far less.

[lavonthurston77]

So even if you have a high static pressure that still don't matter ml series 1.78 mm-H2O and Fan Airflow 47.3 CFM) the LL120 RGB 120mm Dual Light Loop White RGB LED PWM Fan white specs (Static Pressure 3.0 mm-H2O and Fan Airflow 63 CFM) not the LL120 RGB 120mm Dual Light Loop RGB LED PWM Fan black which has specs (Static Pressure 1.61 mm-H2O and Fan Airflow 43.25 CFM)

[c-attack]

Understand static pressure in context of fans specs is the amount of pressure required to reduce the fan's speed to 0 rpm. That means the value is extremely RPM dependent. All fans regardless of design will have some pitiful 2 decimal place value at 100 rpm and even a terrible radiator fan will have a very flattering value at 4000 rpm. My usual example is this other brand fan I used to use to cool a small heat sink. Very impressive ~4.3 mm H2O static pressure rating. However, since it's a 40x40mm fan, you really don't want to put that on your radiator. It only moves about 8 cfm. That is what matters -- the airflow through the radiator. Static pressure is a quick check for fan type, but too easily misinterpreted.

 

In order to realize your 3.1 mm of H2O, you must run the fan at 2200 rpm. At 2100 rpm, it no longer has 3.1 mm of pressure. Most people are not willing to run their fans at that speed. For comparison the ML120 generates 4.2 mm at 2400 rpm as listed on that spec model.

 

Rarely you will see an actual P-Q curve that will allow you to plot a value at RPM X to make fan to fan comparisons. More often, you need to do equalize for RPM on the assumption it is a linear relationship. It's not really perfectly linear, but it will do. Using that here will give you an estimated SP value of 2.25 (1600/2200 x 3.1). This seems better than ML at the 1600 rpm mark. However, you must also do this for the CFM and that comes in 45.8 cfm compared to the ML 47 cfm. Neither 1.2 cfrm nor 0.5 mm are significant differences in fan specification. These two fans also show the flaw in using this logic to compare. If I take the identical frame and blade ML120 Pro with a 2400 rpm max (75 cfm, 4.2 mm) and linearly adjust the values for 1600 rpm (1600/2400 x spec value) I wind up with 50 cfm and 2.86 m. This is the problem with making the estimates, particularly with 120mm fans. The actual values for the 1500 rpm LL fan are 43 cfm and 1.61 mm of H2O. The airflow is reasonably estimated. The static pressure values are prone to error.

 

You won't find anyone claiming the LL are a better radiator fan. That doesn't mean you can't use them. I have a case full of QL fans handling up to 600W of power. I don't gain much more than 1C in coolant temperature by switching in heavy industrial fans at the same speed. So your LL at 2200 rpm may indeed outperform a ML fan limited to 1600 rpm, but that only matters if you are willing endure the 2200 rpm. On the other hand, if you are decking out a 1000D full of fans, you should absolutely by the fan that makes you happy. You will have more than enough fans and surface area for this stuff not to matter and the fans are too expensive not to get the one you really want the first time.