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How much static pressure is created by the ML120 fans?


AMDbigboy
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Was just wondering which fan will provide the best static pressure? I see the Air Series SP120 QE is 1.29 and the SP120 HP is 3.1, the ML120 is 0.2 - 4.2 and the RGB 120 is 2.25. This answers my question mostly, but how much static pressure is created by the Mag Lev fans? 0.2 - 4.2 just doesn't tell me. Anyone know? Thanks.
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I have two of three fans cooling my h100i v2 and they cool extremely well, better than my old thermaltake Riing fans. The only thing I am not happy about is that anything above 1100 rpm then it starts getting noisy.

Generally 140mm fans would be better and quieter and overall better static pressure.

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Static Pressure is a measurement of how much pressure it takes to reduce a fan's speed to zero. So, regardless of fan design, it is very RPM dependent. The world's greatest fan still has a minuscule static pressure number at 100 rpm and a tiny 40x40mm fan can produce a hefty static pressure number at high speeds. Neither of those examples is radiator suitable and it is the amount of airflow you put across the fins that matters.

 

The catch is a fan designed to produce a higher amount of pressure (6 or 7 flat, wide blades, little space between), will move less air than an airflow designed fan (9-15 blades, thin, angled, lots of space between blades). However, that airflow fan may move less air at the same speed when faced with resistance, like a radiator. The greater the resistance, the more likely the 'pressure' designed fan will be able to move more air at the same speed. The final kicker is a fan with flat, wide blades will generally produce more noise at the same speed (ignoring motor qualities). This is the consequence of the design.

 

A compromise of the two designs ends up being a good solution for a lot of people. These hybrid designs offer good airflow, but won't suffer massive drops in performance when up against a filter or radiator. The ML series falls into the hybrid category, as do many 120mm fans. That pressure range of 0.20 to 4.20 corresponds to the min/max speeds. So down at 400 rpm, the pressure necessary to stop the fan is 0.2 mm of H20 and at 2400 is is 4.2. Most 120mm fans do not have a straight line pressure graph between minimum and maximum speeds. It is usually a slow rise, with a steep finish. 140mm fans have a more linear curve. All that means is you won't move a lot of air at the lowest speeds when against a radiator, something you already know. Do not read a lot into static pressure numbers. 3.1 vs 1.29 is a big difference and likely a different blade design. 4.1 vs 3.9 is meaningless. You also have to equalize for RPM, something that is difficult to do on 120mm models without a P-Q curve. Remember most 120mm fans have a sharp uptick in the last few hundred RPM. This only matters if you intend to run in those speeds. It does not mean the higher one will produce more pressure at a lower speed.

 

There is no easy way to turn static pressure into an airflow number against a resistance. You have to test, either with an anemometer or as temperature difference under test conditions. The latter you may be able to find out on the internet. Real airflow numbers are rare. Here is one review that has it, although be careful about leaping to conclusions. Most people don't care about 1-2C is comes at the expensive of noise and/or a displeasing aesthetic.

 

I think most people will be happy changing out the SP120L stock cooler fans for anything from the ML series. While the SP series will "have more pressure" at given RPM, the ML will have more airflow and at medium and higher speeds, it should move more against a radiator and certainly when less restricted. This means they can be used as case fans too with decent airflow and not too much noise. The only circumstance where the SP might be better is where you must use low fan speeds for whatever reason. At lower fans speeds against a restriction, the SP will fare better. So for some sort of office set-up where you might cap fan speed at 1000 rpm or if using the fan for drive cooling, the SP is likely a better choice.

Edited by c-attack
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Static Pressure is a measurement of how much pressure it takes to reduce a fan's speed to zero. So, regardless of fan design, it is very RPM dependent. The world's greatest fan still has a minuscule static pressure number at 100 rpm and a tiny 40x40mm fan can produce a hefty static pressure number at high speeds. Neither of those examples is radiator suitable and it is the amount of airflow you put across the fins that matters.

 

The catch is a fan designed to produce a higher amount of pressure (6 or 7 flat, wide blades, little space between), will move less air than an airflow designed fan (9-15 blades, thin, angled, lots of space between blades). However, that airflow fan may move less air at the same speed when faced with resistance, like a radiator. The greater the resistance, the more likely the 'pressure' designed fan will be able to move more air at the same speed. The final kicker is a fan with flat, wide blades will generally produce more noise at the same speed (ignoring motor qualities). This is the consequence of the design.

 

A compromise of the two designs ends up being a good solution for a lot of people. These hybrid designs offer good airflow, but won't suffer massive drops in performance when up against a filter or radiator. The ML series falls into the hybrid category, as do many 120mm fans. That pressure range of 0.20 to 4.20 corresponds to the min/max speeds. So down at 400 rpm, the pressure necessary to stop the fan is 0.2 mm of H20 and at 2400 is is 4.2. Most 120mm fans do not have a straight line pressure graph between minimum and maximum speeds. It is usually a slow rise, with a steep finish. 140mm fans have a more linear curve. All that means is you won't move a lot of air at the lowest speeds when against a radiator, something you already know. Do not read a lot into static pressure numbers. 3.1 vs 1.29 is a big difference and likely a different blade design. 4.1 vs 3.9 is meaningless. You also have to equalize for RPM, something that is difficult to do on 120mm models without a P-Q curve. Remember most 120mm fans have a sharp uptick in the last few hundred RPM. This only matters if you intend to run in those speeds. It does not mean the higher one will produce more pressure at a lower speed.

 

There is no easy way to turn static pressure into an airflow number against a resistance. You have to test, either with an anemometer or as temperature difference under test conditions. The latter you may be able to find out on the internet. Real airflow numbers are rare. Here is one review that has it, although be careful about leaping to conclusions. Most people don't care about 1-2C is comes at the expensive of noise and/or a displeasing aesthetic.

 

I think most people will be happy changing out the SP120L stock cooler fans for anything from the ML series. While the SP series will "have more pressure" at given RPM, the ML will have more airflow and at medium and higher speeds, it should move more against a radiator and certainly when less restricted. This means they can be used as case fans too with decent airflow and not too much noise. The only circumstance where the SP might be better is where you must use low fan speeds for whatever reason. At lower fans speeds against a restriction, the SP will fare better. So for some sort of office set-up where you might cap fan speed at 1000 rpm or if using the fan for drive cooling, the SP is likely a better choice.

 

WOW, awesome response, thanks! I should have included in my question my intended purpose, for that I'm sorry. I was just looking for the best static pressure for the Hydro Series AIOs. I'm currently using the H105 with the SP120 QE, but for the new build, will be moving up to the H115i. So for that I will use the SP series again. For air flow, I will probably use the RGB if they are available in 140mm. If not, then the MAG LEVs. Thanks for the knowledge c-attack!

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For case airflow, you can use what you want, although I would recommend a pure airflow design (AF120/140 like) or a hybrid, not necessarily an SP120/140LED style fan. If you have any kind of resistance like a dust filter or even a thick honeycomb mesh, the hybrid may be more effective than 9-11 angled blades. I generally prefer the hybrid style, even in my low restriction cases because of the more focused airflow pattern for spot cooling some board components.

 

As for the H115i, we'll have to see what RGB options appear, but the ML140 Pro model is a good choice. I have them on my H110 now. It will move more air than you will even need at the high end and yet is very quiet at 1100 rpm and lower, where you will spend 99% of your time. I've decided I like that option better than the Noctua industrial line that used to be my Summer fan. It is that much quieter at desktop levels. When looking around, you may notice there are no 140mm fans that look like a SP120. All static pressure designed 140mm fans will look more like a hybrid, with a medium number of blades and a medium amount of space. As the fan gets larger, you don't want a lot of extra mass on the blade.

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For case airflow, you can use what you want, although I would recommend a pure airflow design (AF120/140 like) or a hybrid, not necessarily an SP120/140LED style fan. If you have any kind of resistance like a dust filter or even a thick honeycomb mesh, the hybrid may be more effective than 9-11 angled blades. I generally prefer the hybrid style, even in my low restriction cases because of the more focused airflow pattern for spot cooling some board components.

 

As for the H115i, we'll have to see what RGB options appear, but the ML140 Pro model is a good choice. I have them on my H110 now. It will move more air than you will even need at the high end and yet is very quiet at 1100 rpm and lower, where you will spend 99% of your time. I've decided I like that option better than the Noctua industrial line that used to be my Summer fan. It is that much quieter at desktop levels. When looking around, you may notice there are no 140mm fans that look like a SP120. All static pressure designed 140mm fans will look more like a hybrid, with a medium number of blades and a medium amount of space. As the fan gets larger, you don't want a lot of extra mass on the blade.

 

Since I don't like any of the new Corsair cases, only like the original Obsidian Series cases (650D/700D/800D). I've decided to go in a different direction, I will be using the EVGA (can't believe I just said that) DG-87 case. So with a case like that, would you use the MAG LEV or the AF fans? Since aesthetics are important to me, I would prefer to use the RGB fans.

 

Wow, the MAG LEV instead of the SP series for the H115i! OK, I can do that! Like them better anyways.

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Probably the ML series. It looks like the options are 3x120 "Right" (front) and 2x120/140? "Left" (rear). In the 120 size, I like the ML series more than an AF120. Also due to the size of the case and the drive locations, the 3xML120 is more versatile and will give you more air than you can stand -- at the high RPMs. I'm less clear on what will fit in the rear/left/exhaust end. I can't tell if that is 2x140 or 2x120 or either. Normally, I like AF style fans for exhaust. They tend to be quieter and also draw air into the fan from a wider angle than an fan with flatter blade angles. However, with two fans on exhaust duty, I don't think it matters. I might opt for consistency in the build and the ML series can certainly move air either way. There is also something to said for PWM control on some boards. My Asus BIOS has a 60% min for DC fans. On high RPM models, that can put the minimum run speed far too high for desktop work. Most PWM fans can run down to 25% or so. I don't know what board you have in mind, but that is something to balance with the included fan controller, which may require either DC or PWM to work. I did not dig in far enough to discover the answer to that.
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