Windows 7 Case Fans

[seekermeister]

I need to replace a fan in my HTPC, but I have a couple of questions. first, how is a fluid ball bearing different from a regular ball bearing fan? Secondly, one fan caught my eye:

Link Removed

I'm not as interested in the high speed of the fan as I am the thickness (38mm). Am I right in thinking that a thicker fan will produce more CFM than a thin fan at the same speed?

I intend to use this for the blow hole fan atop the HTPC in my bedroom, and since I keep it running continuously, I definitely do not want a high noise level, and I don't know that high CFM is actually a good thing for a fan of this sort, because at high CFM, it might disturb the air flow pattern adversely. But since this fan cost twice as much as most other fans of it's size, my interest in it is just in having the ability to experiment with different speed settings.

 

[Jimbo22]

Thicker won't produce more cfm's only wider blades and bigger fans. In my new case it has 2 200mm case fans and run at 600 rpm and produces 4 times the cfm's as my 120mm fans in my old case did. Depending on what size fans your case can use....for 120mm fans I recommend Nexus. I've used them for years and they're very quite.

As for your question; have a look at this article...but the short answer is fluid bearings are supposed to be the quietest.
The Basics of Case Fan Bearings - Which Bearing is Best? - Gamer's Nexus | Gaming Hardware, Culture, Features, and PC Builds
Bearing (mechanical) - Wikipedia, the free encyclopedia

Nexus Quiet Fan | The World's Quietest Fans | 120MM Real Silent Case Fan | Ideal for a Quiet PC

 

[seekermeister]

Thanks for your response. Even though you say that thicker won't produce more CFM, indirectly you confirmed that it would, because the width of the blades is usually proportional to the thickness of the fan. It would be possible to make a thick fan without increasing blade width, but I can't see why any manufacturer would. That would only increase the cost of manufacture without any benefit.

I've never used a Nexus fan, but I'm wondering if you have ever used one made by Noctua, which currently is my favorite?

 

[Digerati]

I intend to use this for the blow hole fan atop the HTPC in my bedroom, and since I keep it running continuously, I definitely do not want a high noise level, and I don't know that high CFM is actually a good thing for a fan of this sort, because at high CFM, it might disturb the air flow pattern adversely. But since this fan cost twice as much as most other fans of it's size, my interest in it is just in having the ability to experiment with different speed settings.

Blow hole fans are great, but as you note, being right there, noise can be a factor and fan noise in HTPCs is always objectionable. So you are right, you want a very quiet fan in that location. And you are also correct that you do not want to disrupt the desired front to back flow through the case, but since heat naturally rises, my experience is an exhaust blow hole fans are beneficial, regardless.

I also agree that a thicker fan (with all else being equal) will move more air than a similar, but thinner fan simply because the fan blades will be wider, and therefore, will be able to grab and push more air. But the reality is, fans are spinning wings and proper wing design for the most "lift" takes aeronautical principles to the extreme - IF the fan maker invests in that.

The pitch, blade length and width, rotation speed and more affect how much air is moved by any given fan.

As far as that Evercool fan, note it says noise is <43.8dB. That is loud! I would go for something closer to 20 - 25dB in a HTPC. That said, have you checked your temps without that fan? You may not need it.

Finally, if space permits, I would install a larger fan. 80mm fans are not very big. Therefore, they must spin faster to move the same amount of air as larger fans, and faster spinning blades chopping at the air make more noise. So if your case supports 92mm, or better yet, 120mm case fans, I would go that route as they spin slower and move more air, more quietly.

Fluid bearing fans tend to be very quiet because the fluid can cushion vibrations. But "precision" ball bearing fans can be extremely quiet too. The problem is, regardless the bearing type, not all are created equal. Not all fan makers use precision (perfectly round and smooth) bearings. So fluid does not guarantee the quietest. I would avoid sleeve bearings, however. While generally reliable and long lasting, thus suitable for cooling, they tend to be noisier.

 

[seekermeister]

When you speak of the aerodymamics of a fan, you go into an area that I have some knowledge of, because I'm a retired pilot. My studies were not to the depth of an aeronautical engineer, but at least I have a basic understanding.

The only reason I linked the Evercool fan was that I was thinking that by slowing it down, that the sound level would decrease also, and just something to provide a starting point for discussion. The heat in the HTPC has always been higher than desirable, even when I used it for my desktop, because the design of the case wasn't the best for cooling (Antec 1040BII). There is enough space for a larger fan, but I opted for the 80mm because I thought that would provide enough cooling for the location and purpose. I didn't consider the noise level much at that time. I still think that 80mm is big enough for cooling purpose and since the tools that I have on hand makes cutting such holes difficult, I'm reluctant to cut a larger hole.

Do you happen to know of an 80mm fluid bearing fan that would provide the maximum CFM at the minimum noise level that you would recommend? I can't use a sleeved bearing type, even if I wanted to, because of the horizontal orientation that the fan will be installed in.

 

[Digerati]

I can't use a sleeved bearing type, even if I wanted to, because of the horizontal orientation that the fan will be installed in.

If you were to look at and visually compare an 80mm case fan with sleeve bearing vs an 80mm case fan with ball or fluid bearings, there would be absolutely no differences. The size, shape, mounting and electrical connections would be exactly the same. The bearings are located inside the center hub and have nothing to do with orientation. Remember, PC cases come in all sorts of shapes and sizes, from desktops, to towers, to cubes. So horizontal, vertical, diagonal, it does not matter.

I like Antec fans, but for my HTPCs, I use Vantec and Link Removed.

Yes, you are right that slowing down the Evercool will also quiet it down. But that applies to any fan. So I suggest a fan that is quiet from the start, as that should only get quieter when slowed down. Remember, heat is already rising to the top - it will not take much effort to help it along.

 

[seekermeister]

The reason that I spoke of location and orientation limitations of a sleeved fan wasn't because of any outer physical differences, it is because I have read in a number of places that they shouldn't be used in anything other than a vertical orientation, apparently because that a loss of lubrication would occur otherwise. Beyond that I feel that ball bearing drives are quieter.

A response that I got from a dealer selling fluid bearing fans that I asked for a brief explanation of how they differed from any other ball bearing fan was this:

As I understand it, a fluid bearing fan has an
undersized shaft with ridges on the circumfrence [sic], and it sits in a cavity filled with fluid. When the shaft rotates the ridges stur [sic] up the fluid exerting a pressure between the rotor shaft and the bearing arbor, thus centering the shaff [sic].

If true, it sounds like a fluid bearing would be the way to go for any fan. If I remember correctly, I think that is the kind of bearing that Noctua fans use, and I have been quite satisfied with them in my desktop. Unfortunately Noctua doesn't make any 80mm fans though.

 

[Digerati]

The reason that I spoke of location and orientation limitations of a sleeved fan wasn't because of any outer physical differences, it is because I have read in a number of places that they shouldn't be used in anything other than a vertical orientation, apparently because that a loss of lubrication would occur otherwise. Beyond that I feel that ball bearing drives are quieter.

Nah! Not true about orientation. Maybe 20 years ago when only servers were towers and all desktops sat horizontally on our desks, but not today.

And again, while the general category of ball bearing fans due tend to be quieter, there are lousy quality ball bearing fans, and there are top quality sleeve bearing fans - illustrating there are always exceptions to the rules.

 

[seekermeister]

It is those exceptions make making a choice difficult.

 

[Digerati]

Yes they do. That's why I look at dB levels. But even that can be confusing because there is no standard on how to display noise levels. For example, one fan may publish specs that says it produces 45dB @ 5000 RPM and another fan may say 30db at 2500RPM. Which is the better fan? I donno. Not enough information.

 

[seekermeister]

Here is another fan I found that sounded pretty good:

Link Removed

It gave the noise level in sones, instead of dbs, and since I didn't understand that, I Googled this Wikipedia page:

Sone - Wikipedia, the free encyclopedia

If I understand it, it makes this fan appear to be much quieter than others with similar CFM. What do you think?

 

[Digerati]

I don't like the use of sones because they are too subjective. For music, it might be good, but fans generally produce a constant drone. If you look here, you can see that fan pushes out 31 CFM @ 22dBa and that's pretty quiet.

 

[seekermeister]

Do you think that is as good as I can do? I noticed that the warranty for that fan is 6 years, which is equal to Noctuas, so I guess it should be fairly durable.

 

[Digerati]

There are 1000s of fans out there, so as good as you can do? Sorry, but that's homework you'll have to do yourself. A long warranty simply means the makers believes the product will not fail during that time. It does not mean it is better, or will remain better at cooling or keeping quiet. So I agree it is will likely be durable. But let's face it, under $10 is not going to get you the best money can buy - nor be devastating should it fail in 4.

And besides, much depends on the criteria YOU use to define what is "best". Certainly, the best fan for cooling, the primary purpose of a fan, will not be the quietest. Noise is secondary. And quiet fans are not known as the most efficient coolers.

What is your case's fan support in the rear? You can often fit large (120mm or larger) fans in the rear of the case to increase the desired front-to-back flow through the case. The advantage to rear fans is the fan noise may not be so prominent as a blowhole or front fan.

Also, if noise is really a factor, you should look at fan vibration suppressors - often called rubber screws.

 

[seekermeister]

I understand that fan evaluation is somewhat subjective, but I was just asking for your opinion. If you don't feel like stating anything like that, no harm done. I'm considering replacing all of the fans in the HTPC, because they all are only 80mm, and they are getting old enough that I kind of feel that it is time to do so, before anymore actually fails. That means buying 6 fans, because it only has 2 front, 2 back, 1 CPU and the blowhole fans installed (not counting the chipset fan that I just replaced and the video card fan). 6 fans is a somewhat bigger decision that just one.

 

[Digerati]

It is not that I don't want to give an opinion, I am just saying there are 1000s of fans out there, and none provide the best cooling while being the quietest, and costing the least. I have not seen (or heard) that fan, so I can't form an opinion other than what I said already - 22dB is pretty quiet.

6 fans in a HTPC!!! Wow! If you need that many, you need a different case. Ideally, you want a completely passive (no fans) cooling solution in an HTPC. "Only" 2 in front and 2 in back? Most cases provide one, and often none in front.

For sure, I would try to replace any 80mm with 120mm, if your case will allow.

 

[seekermeister]

Thanks, but replacing the case is not within my budget, and none of the fans can be replaced with larger ones, other than the blow hole, which as I said, I don't want to tackle. The primary reason is that all of the hole saws that I know of uses a pilot bit to center the cut, and since I already have an 80mm hole there, that bit wouldn't have anything to guide it. The only way that I can imagine enlarging it is either with a jigsaw, which is difficult to get a precise hole with, or to use a drill press so that the case could be clamped to the table, not needing a pilot bit. I don't have that kind of drill press, and I don't want to take it all apart and take it to some machine shop. So 80mm it shall remain.

 

[Digerati]

You can buy 120mm hole saws but they are not cheap. I would not recommend it for a one-time use. And besides, that would require emptying the case to avoid metal filing getting into the electronics.

Still, that is a lot of case fans for a HTPC. It takes very little graphics horsepower to watch and listen to HD content via an HTPC. And it takes very little CPU horsepower to hand off graphics tasks to a GPU. So compared to regular PCs, a HTPC does not need to be very powerful, thus typically does not generate much heat in need of exhausting.

I guess much depends on the investment you have made into your home theater audio and TV, how much ambient noise you have in your house, and how tolerant you are of fan noise. I have nearly $10K in my home theater so the last thing I want to hear during a quiet passage in a movie is my HTPC fans rumbling away.

 

[seekermeister]

I can understand, if I had that much money in it, I would expect a lot more from it than I do, but actually it is the predecessor to the desktop I now have, just reutilized as the HTPC. I agree that it doesn't take a lot for an HTPC, and should run cool and quiet, but it does neither. I don't mind the noise too much, because I had become used to it over the years, but it runs a lot hotter than I care for. That is why I added the blowhole, and am considering buying a new Noctua CPU cooler for it. I'm hoping that when I get the blow hole working properly, it might also cool the video card down some.

EDIT: I'm curious, since we agree that it doesn't take a lot for a HTPC, why did you spend $10,000 on it?

 

[Digerati]

Not the HTPC - on everything else (speakers, big screen TV, BluRay player, and receiver). To be sure, if I had an unlimited budget, I could easily spend $25,000 or more on just the speakers! But I am crazy, not stupid. At 61, and many years working around Air Force flightlines, and many years more listening to rock, I know my hearing is not up to that level of audiophile equipment.