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140mm Fractal stock vs 120mm Arctic P12 PWM PST

Vincenterino
By Vincenterino
in Cooling
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Go to solution Solved by Lurking,

Arctic are just average fans, so are Fractal. Fractal probably has much better consistent quality. Arctic has lot of duds that have weird noises. 140mm is better than 120mm all the time. You would need a very premium 120mm fan to be better than a really crappy 140mm fan. It's just physics and the inherent advantage of the much larger cross section of the larger fan.

 

Noctua 140mm may be an actual upgrade. But Arctic isn't. The only good thing about Arctic are the cheap 5-packs. But this tells you they sell by price, not quality.

 

It isn't just the larger fan, you also use the larger section of the dust filter to move air through. Much lower velocity of air through the filter if you use the larger fan. Pressuredrop and noise increases to the square of velocity increase. 

Posted
16 hours ago, RevGAM said:

Could you explain how total efficiency is 77 when the curve peaks below 7000? I'm assuming there's an equation involved. .... If I haven't misunderstood, you are suggesting that the AF and SP listed may be "bad" because we don't have a chart like the example you provided, but you/we have no way to know since they have deliberately withheld data. I see no reason why manufacturers do this because there is no single excuse that would justify every company doing it, and all the excuses still wouldn't cover all the companies, so it smells of chicanery or malfeasance.

Efficiency of a fan is based on how much air-power (flow times pressure) you get out of the fan shaft power (or electric motor inc. its efficiency). The entire curve is based on measurement. the manufacturer measures (or hires a lab to do) the low rate and pressure over the entire curve and measures power consumption of the motor. It isn't very important for small PC fans, but for real life commercial fans power consumption is important. For a given fan application you could need a 1.5hp motor, or a 5 hp motor. so yes, fan efficiency matters. 

 

Every manufacturer gives you the fan curve on their website/PDF and most also have a selection software that has those built in. when you select the fan, you will see where your application is on that fan curve. Only the PC industry gets away with not providing necessary data. 

 

Below a pic of how they test fans to get the curve. you also see, at the maximum pressure (left) the flow is blocked off. So everyone who buys a PC fan based on the "pressure", does so based on pressure at zero flow. if zero flow is your objective, fine. But i though we wanted flow... so we should select a fan based on performance at a flow. 

 

Module 34: Matching the fan to the ventilation system – CIBSE Journal

AMD 9 7900 + Thermalright Peerless Assassin SE

Gigabyte B650m DS3H

2x16GB GSkill 60000 CL30

Samsung 980 Pro 2TB

Fractal Torrent Compact

Seasonic Focus Plus 550W Platinum

W11 Pro

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Posted
8 minutes ago, Lurking said:

Efficiency of a fan is based on how much air-power (flow times pressure) you get out of the fan shaft power (or electric motor inc. its efficiency). The entire curve is based on measurement. the manufacturer measures (or hires a lab to do) the low rate and pressure over the entire curve and measures power consumption of the motor. It isn't very important for small PC fans, but for real life commercial fans power consumption is important. For a given fan application you could need a 1.5hp motor, or a 5 hp motor. so yes, fan efficiency matters. 

 

Every manufacturer gives you the fan curve on their website/PDF and most also have a selection software that has those built in. when you select the fan, you will see where your application is on that fan curve. Only the PC industry gets away with not providing necessary data. 

One thing I'll add, when you have a whole data center worth of small PC fans the small gains add up to a noticeable change in power consumption and heat generation. for example, 0.1A vs 0.3A is 200% more wattage consumed at full duty cycle. 100 fan server rack x 0.3A = 3A x 12V = 360W vs 120W. It's like adding a RTX 4080 worth of heat that is don't nothing but reducing performance and costing electricity. 

In portable applications small fan efficiency is even more important due to power, weight and form factor constraints.

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Posted
11 hours ago, TeraSeraph said:

One thing I'll add, when you have a whole data center worth of small PC fans the small gains add up to a noticeable change in power consumption and heat generation. for example, 0.1A vs 0.3A is 200% more wattage consumed at full duty cycle. 100 fan server rack x 0.3A = 3A x 12V = 360W vs 120W. It's like adding a RTX 4080 worth of heat that is don't nothing but reducing performance and costing electricity. 

In portable applications small fan efficiency is even more important due to power, weight and form factor constraints.

This is true, even if it is a small fraction compared to CPU and GPU et al. For efficiency, larger fans also rule. 

 

Ultimately noise is wasted energy. So, silence and efficiency are not mutually exclusive. A well designed system and fans can be both silent and efficient.

AMD 9 7900 + Thermalright Peerless Assassin SE

Gigabyte B650m DS3H

2x16GB GSkill 60000 CL30

Samsung 980 Pro 2TB

Fractal Torrent Compact

Seasonic Focus Plus 550W Platinum

W11 Pro

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