Premium Computer Fans Tested: Do They Keep Your Computer Cooler?

8 responses to “Premium Computer Fans Tested: Do They Keep Your Computer Cooler?”

1. 

   dorsy99

   October 1, 2014

   I have used both cheap and premium, and while it doesn’t make that much difference the extra $5 could get you a better bearing (meaning the fan lasts heaps longer) and PWM control (giving the motherboard the ability to only spin it up when it needs it). This helps with sound and power usage. If you leave your computer on 24/7 or are putting the fans in a home server I reckon it’s worth the cost.

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2. 

   woofwoof

   October 1, 2014

   1) If you have fans blowing out, do you really need fans blowing in? The air must get in. So the extra fans are extra noise.
   2) Run multiple fans at lower speed to get the same volumetric flow with less noise. Run 12v fans on the 5v supply if you don’t want/have a controller.
   3) Fans inside on components whilst necessary to cool the component transfer heat around the case but not out of the case. For instance my CPU fan sucks from the heatsink and exhausts through a hole in the case, it is also big and slow.
   Just some ideas.

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   1. 

      awnshegh

      October 1, 2014

      Just on point 1 – it’s actually better to have them all blowing air in. You want a high pressure cell in the case – that reduces dust build up on your parts. I remember seeing tests on this about 10 years ago but as it’s so long ago I can’t find the link.

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      1. 

         kesawi

         October 2, 2014

         For similar reasons listed by @ryukrieger below for having all fans blowing out, having all fans blowing in will be just as inefficient.

         The key to removing heat from inside a PC case is to have minimal airflow restrictions through the case. You need fans to assist the air to move both into and out of the case. To create positive pressure you need more fans blowing in than blowing out. The intake fans will need to be filtered to have any impact on dust.

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         1. 

            woofwoof

            October 2, 2014

            It would appear to be a benefit to having a push and pull arrangement to create a definite direction of flow from the cool area in the bottom of the case to the upper hot section and then out. However I cannot see how it is more efficient if the holes at the bottom of the case were as large as the holes of the exhaust fans.

            Consider a tube with a fan on each end with a nominal 0.25 cubic metre / min flowrate. Besides a bit of friction on the walls when attached to the tube the flow rate at the other end will also be 0.25 m^3/min. Attach another fan to the other end of the tube and the flow rate will still be 0.25 m^3/min. The 2nd fan might overcome a bit of friction on the walls, but there will be little difference. Do this again with a tube of twice the area, lets just use 2 tubes joined coaxially with a fan on each, we will get 2X the airflow. So 2 fans at the top of a case and a hole at the bottom of the case equal in size to the 2 fans will have twice as much airflow as a push pull arrangement, and be twice as efficient. The reason I think pull is better than push is because you already have the PSU fan pulling air out, so pushing air in has little effect unless it has significantly bigger airflow than the PSU fan.

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   2. 

      ryukrieger

      October 1, 2014

      1. Fans only blowing out will create negative pressure, that means that there isn’t enough air inside the case to be blown out, forcing the air to be “forcefully” taken in via any and every gap, imagine the amount of dust that could come in. Well, you could argue having a fan would be the same without dust filter, but the next thing is efficiency, there’s not enough air to be blown out, so by forcefully taking things in from the outside, it can’t replenish and ensure there is enough air going through the case at all time. So in short: Negative Pressure, More Dirt, Less Efficient Airflow.
      2. As long as you have the space, yeah, that works.
      3. Fans for the components are mainly used in conjunction with heatsinks, that’s why, you can have a heatsink to cool passively. but that’s because the heat in the heatsink can (but not absolutely required) needs to go somewhere, and if it gets in a general area in the case, the fans exhausting and taking in air will be able to blow that hot air away. It’s a process of multiple airflows. That’s why when the heatsink fans aren’t pointing somewhere out of the case, they’re usually positioned in the same direction as the airflow. But your point is valid. (Also, how the heatsink is made affects the cooling efficiently, too, if it’s badly designed, the performance won’t be worth the size or price)

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      1. 

         woofwoof

         October 2, 2014

         I think you make a very good point about negative pressure, i.e. outgoing fans only, will mean the intake air is coming from every crack and hole, as opposed to a large hole with a fan (and hopefully some filter). So more dust and fluff will be drawn from the floor than a front mounted fan, as we do tend to keep the area in front of such equipment cleaner. Other reasons for a front mounted fan are to ensure air is delivered from the front, as the rear is often constricted and hotter. It sets up a flow of cool air from fairly low at the front usually near the bottom of the case, the exhaust fans set up a low pressure area at the top of the case. This ensure an upward flow of cooler air that assists the normal convective flow of hot air upwards.

         I am not convinced there is going to be much difference between positive or negative pressure in the case with regard to dust deposition and efficiency. The 3 factors that I believe are probably most important are where the air intake is from, the turbulence of the air, and static electricity. Dust and fluff has to settle or stick. I think the latter is more important. There is no shortage of fluff stuck to any constriction but it also sticks to plastic fans where it certainly cannot settle, and I presume this is due to static buildup caused by the airflow.

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         1. 

            ryukrieger

            October 4, 2014

            Sorry for the late reply,
            Yes, you’re right, by having only outgoing fans, that means gathering up dust every possible entrance, especially the ones near dustier areas, too. Just recapping what you said at this point, though.

            Imagine this, (this is just for visualization, the numbers don’t calculate that way in real life), you have 10L (liters) of air in your case. Your intake and outtake take in 20L per minute, completely replacing the air within 30 seconds, that’s neutral pressure (in a way). If intake > outtake (20L intake, 10L outtake, for example), that means it will use other gaps in the case to flow the other 10L of air out, that’s positive pressure, PREVENTING dust from entering via those gaps at the same time, which is good. If outtake > intake, that means the air will have to be taken in from other gaps, taking dust in from those gaps, but if the gaps don’t supply enough air, then they can only exhaust as much air as those gaps take in (It’s like spending more money than you can earn).
            Assuming you have dust filters, positive pressure means most of the dust will be hitting that filter, that’s good. Negative pressure, dust won’t be hitting that dust filters from the gaps that aren’t filtered.

            In short, in term of efficiency, it’s always better to have more coming in than out (think your income and spending) just in case you might be short of them. In term of dust-filtering, it’s always better to know where most dust would be coming in, applying proper filter to that place. (And yes, static plays a part, too, even without filters, that means a lot of dust will be collected on the fan instead of going into the system, making it easier to clean at the same time) Also your point, too, taking in air from places with less dust (but let’s face it, when the sun rays are visible on certain times of days, you see tons of dust floating in the air, so that doesn’t really help much)

            On pull-pull or push-push, unfortunately, I have not the experience or see/hear anybody with experience (or I missed them completely), but if I have to guess, I “guess” that it wouldn’t make too much difference.

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      2. 

         woofwoof

         October 2, 2014

         What do you think of the thought experiment above about 2 fans arranged in a pull-pull or push-push arrangement being 2X as efficient as a push-pull in terms of airflow?

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