Long lasting fans?

yoitsmeremember · Post by **yoitsmeremember** » Wed Sep 17, 2008 4:45 am

I've had my PC for about a year now, and already one of the rear fans shakes violently when I turn it on. They were nice and quiet thanks to my fan controller, and I'm sure there are plenty other fans that would be as well.

But, what will stand the test of time? These are ball bearing fans, and while certainly not the most expensive (kingwin), I'm not sure whether going more expensive is really a fix or if I should just try some sleeve fans.

What are your experiences with fans that have lasted you at least 2 years? Are they mostly sleeve, or are some ball bearing? Anything else I should consider when looking at reliability?

Thanks in advance.

frenchie · Post by **frenchie** » Wed Sep 17, 2008 5:09 am

Maybe more expensive is better :
- Arctic cooling fans (non PWM) come with a 6 years warranty

and have a 400'000 h MTTF ... (that is 45 years if I'm correct...)

- Noctua fans have an MTBF > 150.000 h and come with a 6 years warranty just in case....

teejay · Post by **teejay** » Wed Sep 17, 2008 6:32 am

My server machine uses 4 Nexus fans (2x 120, 1x 92, 1x 80) and has been running nearly 24x7 for about 4 years now. It is possible that they have gotten louder over time, but none of them have failed or caused problems. One fan is directly outside the PSU and the other one is mounted in the HSF (Zalman 7000), so thermally pretty challenging environments... no problems yet.

lm · Post by lm » Wed Sep 17, 2008 7:17 am

from http://en.wikipedia.org/wiki/Mean_time_between_failures

Mean time between failures (MTBF) is the mean (average) time between failures of a system, and is often attributed to the "useful life" of the device i.e. not including 'infant mortality' or 'end of life' if the device is not repairable.

MTBF works better with solid state devices that don't generally degrade notibeably, before just failing.

Fans however have bearings that degrade over time until the fan is not usable anymore.

So 45 years of MTBF in a fan means that if you replace fans at their end of life, the early failures only happen once per 45 fanyears.

Scythe S-FLEX line of fans have the following:

MTBF: 150,000 hours
* 150,000 hours of MTBF is measured under the 25C (77F) ambient temperature.
* MTBF of normal ball bearing Fan: 50,000 hours
* MTBF of normal sleeve bearing Fan: 20,000 hours

However numbers like these are probably measured this way: Run a bunch of thousand units, and when the first one fails, multiply the time by the number of units and that's your MTBF. If all the fans run flawlessly for 150 hours, that does not tell much about how one fan handles several years.

This large range of MTBF numbers is puzzling. So there's claims as high as 400k and as low as 20k. Maybe those are just as dependable as the dB numbers claimed by fan makers.

6 year warranty, that is what I would trust best

Post by **NeilBlanchard** » Wed Sep 17, 2008 8:30 am

Hiya,

The GlobalWin fans have ceramic bearings that are supposed to last a very long time, in harsh conditions.

dhanson865 · Post by **dhanson865** » Wed Sep 17, 2008 8:59 am

If you are replacing 120mm fans you have several options.

At about $4 a piece after S&H I'm happy with Yate Loon fans even if I have to replace them a few years down the road. http://www.jab-tech.com/YATE-LOON-120mm ... -3009.html

At about 3x that price you can get a Scythe SFlex that will last longer. Will it last 3x longer, I'm not sure but it is a worthy choice. http://www.scythe-usa.com/product/acc/0 ... etail.html

Inbetween the two in price is the Scythe Slipstream http://www.scythe-usa.com/product/acc/0 ... etail.html like the SFlex it comes in your choice of RPMs but like the Yate Loon it is a sleeve bearing fan.

Any of the 3 would be a fine choice. I've used the Yate Loon for years and don't notice any problems with longevity and I expect the Scythe fans to be even better (worth the price difference in build quality).

You have some variety to choose from and any of the above would be better than those chattering ball bearing fans in my view.

Placid · Post by **Placid** » Wed Sep 17, 2008 10:49 am

I have a sleeve bearing 2800 RPM Delta fan that has been running for 7 years before replacing it a year ago. It still works perfectly, although it is so noisy, that by a silencer's standards, they would think it ruptured their ear drums.

whiic · Post by **whiic** » Wed Sep 17, 2008 11:35 am

Noctua's fans supposedly have fluid dynamic bearings like Scythe S-FLEX does.

Sleeve bearings and FDBs share some simility in lack of bearing noise but FDBs have the capability of sealing the lubricating oil (sleeve bearings also have oil) so that long-term durability is better. Sleeve bearings tend to dry out in use... but this is a problem I've only had with small diameter sleeves, especially 40mm fans have been horrible for me. They spin so fast that centrifugal "force" dries the bearings and with only a thin axle (often no even perpendicular to hub) to keep the blade assembly in place these fans become severely unbalances when lubricating oil doesn't cushion the axle.

BBs are long-lasting like FDBs but they always make some noise when operating, new or aged. Might get worse over time.

FDBs are the best, IMO. Whether sleeves or BBs are better, it depends on priorities. If one wants to undervolt the fan, sleeves are quieter. And running slow probably slows down the rate oil escapes the bearing surface so it'll run nicely for many years. And if it starts to make noise, one should remember that sleeve bearing fans are easily re-lubricated: remove the sticker, remove the plastic locking ring, remove fan blades, reattach the sticker, add a drop or two of engine oil to bearing, put fan blades back. (It doesn't need the locking ring, really. That ring only makes more noise.)

It'd of course be easier to just remove sticker, add a drop of oil and reattach sticker... but in case you accedentally smear oil where sticker is to be placed, good luck trying to get it stick there. (Isopropanol helps. Also, Loctite helps attaching the sticker if original glue doesn't reattach.)

I haven't had to do this for any fans bigger than 40mm. Well, because most of my 60...92mm fans are BB. And 120mm fans are usually pretty solid. Anyway, you could try relubricating it. It doesn't cost anything to try. If you don't have engine oil, then use some cooking oil. I've done it with that too... though I try to avoid it... I don't want mold growing inside my computer later on.

yoitsmeremember · Post by **yoitsmeremember** » Wed Sep 17, 2008 3:24 pm

whiic wrote:BBs are long-lasting like FDBs but they always make some noise when operating, new or aged. Might get worse over time.

Yeah, that's exactly the problem. Sounded silent when I bought them, and now louder than hell.

FDBs are the best, IMO. Whether sleeves or BBs are better, it depends on priorities. If one wants to undervolt the fan, sleeves are quieter. And running slow probably slows down the rate oil escapes the bearing surface so it'll run nicely for many years.

Maybe I will spend the extra money and get some nice FDBs, but if sleeves last as long as you say they do at slow speeds, I'd definitely get them over BBs for this time around.

As far as MTBF goes....well, I can't say that's the greatest measurement for fans, simply because I doubt the consistency of measurements taken between manufacturers, but more importantly, a noisy fan isn't considered a "failure" in their eyes. In mine, however, it is, and that's why I won't use it when judging fan quality.

Anyway, thank you very much for the recommendations, I'll start buying some fans tonight.

sjoukew · Post by **sjoukew** » Thu Sep 18, 2008 12:35 pm

In an old machine which is running for more than 5 years I do have 2 papst fan's 80mm. One in the psu and one as case fan. If you ask me they run like they are new.