I can't understand why people stick to blowing CPU fans!!!

Cooling Processors quietly

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Cerestes
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Post by Cerestes » Fri May 21, 2004 3:48 pm

Pirata wrote: @ Rusty075: you talk about a new alpha, newer than the 8942?
The newest alpha i'm aware of is Model "S-PAL8055FU", only retailer I can find with it is newegg, and its $45 after shipping.

I've got a great system setup in mind that will require a 'sucking' CPU heatsink.

Anyone heard anything about the newest Alpha?
Directron has the ALPHA PAL 6035 for $13 (pre shipping). I'm having a hard time justifing 3x the price for a newer model...

Planning on using it on a ~2500+ mobile barton.

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Post by sthayashi » Fri May 21, 2004 4:37 pm

Cerestes wrote:The newest alpha i'm aware of is Model "S-PAL8055FU", only retailer I can find with it is newegg, and its $45 after shipping.
...

Anyone heard anything about the newest Alpha?
I HAVE one. What do you want to know about it?

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Post by Rusty075 » Fri May 21, 2004 4:38 pm

Pirata wrote:@ Rusty075: you talk about a new alpha, newer than the 8942?
Yes, the 8952

There's also the new Socket A version, the 8045 Ther're their first new HS's in 2 years.

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Post by Cerestes » Fri May 21, 2004 5:39 pm

Wondering how it performs as a heatsink, haven't seen a decent review of it yet. Is it worth an 3x the price of the older Alpha 6035?

Happen to have any comparrison figures? System before/after, with something else, etc?

I'm going to be running a HS in 'suck' mode, wondering if it'll out perform a SLK-900A when paired with a M-Barton 2500+

Motherboard doesn't have mounting holes, so its limiting my options.

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Post by Rusty075 » Fri May 21, 2004 5:44 pm

Frostytech has a review of the 8952. His reviews aren't as good as they used to be, but they're still pretty good.

It should be noted that it's being tested with a Delta screamer (56dBa)

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Post by zak » Sat May 22, 2004 12:07 am

Hmmm with th eCPU fan in 'suck' mode, doesn't the motherboard miss quite some cooling causing the same burn-up effects as some watercoolers report?

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Post by Pirata » Sun May 23, 2004 2:50 pm

After all this I'm trying to draw some conclusions that I can take home with me. The thing, as I see it, goes so:

If you have a look at the top of the silentpcreview heatsink rank, you'll see that the highest score go to blow fans (that includes radial blowing). While these blowing HS reach a punctuation of up to 8+, the nearest sucking HS scores 7+. So you can have lower RPMs in the CPU fan if you go blowing than if you go sucking. The problem about blowing is the higher case temps, which require higher RPMs in the case fans, which can probably counter the noise reduction achieved in the CPU fan.

Does anyone agree?

In this thread

http://forums.silentpcreview.com/viewtopic.php?t=10549

I am discussing an idea I've had that has to do with sucking and blowing. It's about combining both of them on the CPU HS via ducts. Maybe you'll like to have a look at it.

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Post by Trip » Sun May 23, 2004 3:07 pm

I don't see a post by you in that thread.

Just in case you missed it: http://www.viperlair.com/reviews/case_c ... 1/p2.shtml

These two are very ductable but top heavy and with poor clips (can't be transported)

Bluefront ducted a Heatlane Zen fanless heatsink to his 12cm PSU, also. That might work with a duct to the case exhaust.

EDIT: One idea I had in a previous thread was to duct the intake of a blow heatsink and then duct the exhausting air from the bottom of the heatsink out. It would require a near seal to the mobo though (to increase air pressure inside ducts) and a second seal where the inner intake duct cuts the outer outtake duct.

Opening intake vents will help with exhaust ducts by lowering negative pressure.

I do not fully understand the countercurrent heatsink model, so if you're adding to that... heh.
Last edited by Trip on Sun May 23, 2004 3:23 pm, edited 3 times in total.

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Post by Rusty075 » Sun May 23, 2004 3:15 pm

Pirata wrote:....The problem about blowing is the higher case temps, which require higher RPMs in the case fans, which can probably counter the noise reduction achieved in the CPU fan.
Why do you think that your case temps will be lower sucking than blowing?

You've got the same heat being produced in there, with the same amount of air being exhausted. The temps are going to be very,very similar unless you're controlling the airflow with ducting. And the ducts could just as easily be designed to work with sucking HS's as with blowing.

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Post by Trip » Sun May 23, 2004 3:24 pm

Rusty, you've seen an exhaust duct designed for a blowing heatsink? How does that work? Oh, are you referring to the counter current heatsink? Heh, dang I need to look at that again.

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Post by Rusty075 » Sun May 23, 2004 3:32 pm

There are plenty of them Trip, ARM uses them in every system they sell: Image

I wasn't saying that the duct had to be an exhaust duct, an intake would work just as well

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Post by SpyderCat » Sun May 23, 2004 3:37 pm

Trip wrote: I do not fully understand the countercurrent heatsink model, so if you're adding to that... heh.
I didn't know you were THAT shy Trip.
Just ask! :lol:

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Post by Trip » Sun May 23, 2004 3:42 pm

Rusty, that will add to the case temp though. Pirata's point is that a system should run quieter if the heat is exhausted immediately.

Pirata, I just skimmed through the review. I'll read through it again and post a question.

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Post by Rusty075 » Sun May 23, 2004 3:45 pm

Trip wrote:Rusty, that will add to the case temp though. Pirata's point is that a system should run quieter if the heat is exhausted immediately.
2 questions:

1. How will it that add to the case temp?
2. So what?

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Post by Trip » Sun May 23, 2004 4:17 pm

1. b/c heat is being blown into the case
2. well, it takes another fan to exhaust that heat. EDIT: the higher case temp will heat up the PSU, GPU, HDD, and whatever else unless they all have intake ducts.

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Post by Trip » Sun May 23, 2004 4:26 pm

The computer should be able to run with less case airflow.

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Post by Putz » Sun May 23, 2004 5:00 pm

I agree with Trip, although in practice, the difference is minute, and in many cases overshadowed by other differences (such as the relative inefficiency of heatsinks in the "suck" configuration, requiring higher RPMs for equal cooling).

For instance, in that ARM Systems computer, you could duct the exhaust fan from the CPU heatsink, which would keep overall case airflow almost the same (except for the increased resistance created by the duct/heatsink), but remove the need for the fan on the heatsink itself completely. Clearly, the intake duct does not remove the need for a CPU fan, or a case exhaust fan. Theoretically, the case temps would drop as well, since CPU heat would not be recirculated in the case. However, if that particular setup required significantly higher exhaust fan RPMs, the net noise might be equal or even higher, so it's not always a win-win strategy.

That said, the strategy does work in some cases. It works wonders for my old PIII and Celeron systems, and I'm experimenting with it in my Sonata/Palomino right now (pending parts arrival).

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Post by Pirata » Mon May 24, 2004 4:25 am

Well:

1-non countercurrent cooling: look at the figure in the countercurrent review. (2nd page I think) the cool air is heated up harshly right at the beginning of the heatsink, its hottest section, because of the huge temp difference. This heated air travels all the way, transferring heat back to the heatsink. Countercurrent avoids this. The heating up of the air happens right before the air is exhausted.

Well. That's what I understood. It's difficult to see. I wonder if it is true, and if it could be found in a thermodinamics book. If anybody had a rigorous theoretical explanation at hand, it'd be about time to show it.

2-if you use sucking and duct the heated air right away of the case, temps will be lower because of the same as in 1: hot air doesn't even touch sensigble components. Cons: you can't use outside air to cool the heatsink, and the best heatsinks available are blowing ones. Anyway, if you look at the heatsink top of the pops list, you'll see that differences are not that huge. Thus, you can save rpms in the case fans, maybe even make away with them if you put the PSU out of the case (?), but you'll have to put more rpms in the CPU fan.

3-How could we use outside air to cool the fan? We'll need a 2-way ductable heatsink like the aerocool ht 101 or the coolermaster hyper 6. But experts say that if you duct 2-ways, you'll need high rpms because of air impedance... My point is: no fast-spinning 80mm CPU fan and no case fans, but 2 120mm fans spinning at average speeds could be a win-win situation.

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Post by bomba » Mon May 24, 2004 5:31 am

With an HT-101 or other high tower style heatpipe CPU cooler, the fan can be easily mounted as suck or blow with the exhaust ducted out the back of the case to avoid expelling heated air inside the case. Exhaust fan may be mounted on the case or the cooler and/or multiple fans may be used. Anyone tried this or have plans to try?

The Achilles heel of the HT-101 seems to be the inflexible mounting such that on most motherboards, the orientation is up & down rather than front to back. Perhaps this is not the case w/ Thermaltake's version.

Ok here's the question for those familiar with heatpipes. My understanding is that heatpipes are filled with a type of refrigerant which is vaporized from CPU heat. The vapor rises into the cooling fins, is cooled & condensed. Condensed refrigerant flows back down to the CPU heat transfer block and the cycle is repeated. What is the preferred mounting orientation for a heatpipe CPU cooler? Seems to me that the CPU must be horizontally mounted (desktop case) for this to work correctly. If so, this is certainly a severe limitation.

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Post by Rusty075 » Mon May 24, 2004 7:04 am

Pirata, I think you may be confused about counter-current heat flow. Heatsinks in "blow" mode, like 99% of them are, are counter-current. "Suck" heatsinks, like the Alpha's, and like the type that you're proposing that everyone use, do not use counter-current. So all of the efficiency advantages that you discussed work against the entire argument you are trying to make.

The whole point of this was to demonstrate to Pirata that there is good reason why people stick to blowing CPU fans, not to propose that it should only be done one way or the other. It's a perfect example of "Your Milage May Vary" Whatever works for you...

But having said that, ducting CPU air in, rather than ducting exhaust air out does have some significant advantages:

1. The CPU is the largest single source of heat, and it is also the most heat sensitive. It makes sense that it should be given the coolest air possible. A "suck" heatsink forces the CPU to be cooled with air that is 10-15° warmer than the ambient. (unless you duct it's intake and its exhaust) That will require more CFM, and more dBa to achieve the same CPU temps.

2. For the end user, there are more efficient "blow" HS's than there are "suck" ones.

3. For the same RPM, a fan blowing is quieter than a fan sucking.

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Post by Pirata » Mon May 24, 2004 7:41 am

@Rusty075: oh my dear boy. You read something worng. I've never said that countercurrent cooling applies in suck mode. Read again, man.

As to your points:

1-Yeah the CPU is terribly warm. Why to spread the really hot air coming from the CPU all over the mainboard components, then the HDs, etc? Take it away as soon as you can! I even believe that in an average profile PC, if you duct the air away and put the PSU out of the case, case fans can be disposed of.

2-The differences are not huge, moreover with the new alphas. I wonder why these new alphas are not reviewd by MikeC. They've been around for quite some time.

3-I think you're right on this one and I guess it is the same as a vacuum cleaner's input hole: if you bring your fingers close to the hole, air turbulence begins to make noise. This doesn't hapen with a fan (the ones people use in summer, not the PC ones).
But for this problem there is the Thermaltake Ducting Mod, right? ;-)
Have you people already tried it?

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Post by SpyderCat » Mon May 24, 2004 8:48 am

Rusty075 wrote: 1. The CPU is the largest single source of heat, and it is also the most heat sensitive. It makes sense that it should be given the coolest air possible. A "suck" heatsink forces the CPU to be cooled with air that is 10-15° warmer than the ambient. (unless you duct it's intake and its exhaust) That will require more CFM, and more dBa to achieve the same CPU temps.
Only half true Rusty:

It makes sense to cool it enough.
It also makes sense the protect the PSU from sucking up the CPU's heat.
Without an exhaust duct you still need a fan to evacuate the hot air in the case.
Cases with an exhaust-duct don't need to be 10°-15° over ambient, 6°-8° is more typical.

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Post by Trip » Mon May 24, 2004 9:00 am

a duct thread

thread on a thermaltake ducting mod

Of course, Rusty is right that blowing heatsinks allow for a quieter system overall right now - i should add he's tested these things a lot more than I have (which is very little) but I just think a ducted exhaust has potential. The counter current zalman cooler is a great example though requiring some modding to make.

Maybe a desktop setup with one of the 80mm exhaust holes ducted for the CPU exhaust and allowing the PSU to help with case exhaust may really help or a positive pressure mini tower case with a straight duct like ARM uses.

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Post by Rusty075 » Mon May 24, 2004 11:51 am

Pirata wrote:@Rusty075: oh my dear boy. You read something worng. I've never said that countercurrent cooling applies in suck mode. Read again, man.
Ok, I'll try to explain this more carefully this time:

This whole thread started with your little rant about blowing heatsink fans:
Pirata wrote:Why the hell would anybody use a HS and a blowing fan on the CPU to spread really hot air all over the case?

Why doesn't everybody use heatsinks like the alpha, sucking hot air to the outside through a duct? What's the point on using blow heatsinks? I can't understand it!
Then you go on to explain why concurrent flow isn't as good as counter-current flow:

Pirata wrote:1-non countercurrent (aka concurrent) cooling: ... the cool air is heated up harshly right at the beginning of the heatsink, its hottest section, because of the huge temp difference. This heated air travels all the way, transferring heat back to the heatsink. Countercurrent avoids this. The heating up of the air happens right before the air is exhausted.
Which is exactly right.

Counter-current is more efficient because it maintains a thermal gradient between the air and heatsink over as large a surface area of the heatsink as possible. At the top of the heatsink, the air is cool, and the heatsink only warm. As the air travels down the sink, it picks up heat energy and warms. But the surface of the heatsink is also getting warmer the further down you go, so the temp difference remains higher. (transfer of heat is proportional to temp difference, the bigger the difference, the bigger the rate of transfer) By keeping the gradient as constant as possible, you get maximum use out of all of your surface area and heatsink mass.

With a concurrent flow, the coldest air hits the hottest part of the sink first, which sounds like a good thing. And it is, at least right there. At that point you're getting the maximum rate of heat transfer possible. But as the air goes upwards in the sink, it gets warmer as the sink gets colder. The gradient between the air and the sink shrinks, shinking the rate of transfer. And yes, if the situation is right, at the top of the sink you could actually have the air heating the sink, the exact opposite of what you want. (note that such a condition would be transitory, the sink would eventually become equal to the air, and the top portion would just cease to do anything at all) So in a concurrent flow some parts of the heatsink aren't being used as much as others, reducing the efficiency.

That is why nearly every high-efficiency industrial heat-exchanger uses counter-current flow.

Blowing heatsinks=counter-current
Sucking heatsinks=concurrent


So in summary, you started off by saying that anyone who uses a "blowing" heatsink is stupid, but then properly explained why a blowing heatsink is more efficent than a "sucking" one.

That was the point I was making.


To briefly cover some of the other aspects:

-The CPU is the most heat sensitive of any part of the computer. Your mobo will be just as happy at 50° as it is at 40°.

-Intake ducting the CPU only effects the PSU if you are using the PSU as a case exhaust...which you shouldn't be. As one of the other big heat producers, it should have its own supply of cold air.

-Intake ducting doesn't increase the need for case exhaust. You're blowing air into the case, it will find its own way back out. In that regard it's equal/opposite to the idea of ducting the exhaust.

-A difference of 5-10° in the temp of the air blowing over the CPU will make a big difference in the airflow required to cool it. An example:

Say you've got a typical 70watt CPU and a typical SLK-800, with a typical L1A.

Duct in ambient air, at a temp of 25°, you can get a CPU temp of 53° by running your L1A at 7 volts. That's 14dBa....very quiet, even by our standards

Suck case air through it at 33°, and to get to a CPU temp of 53° you need to run your L1A at 12volts. That's 24dBa...louder than most of us here would consider acceptable.

It's all about the °C/W and the Delta T. And this example assumes the unrealistic hypothesis that the SLK would perform equally in both directions. As explained above, it won't, so in reality you've never be able to get to 53°



Ok, back to the other points:

-The new Alpha's haven't been reviewed most likely because no one has offered (or agreed) to submit one....feel free. :lol:

-The Thermaltake duct thingy has only been marginally successful for most people. It actually seems to be more effective for blowing heatsinks than sucking, since it reduces the impact of the hub "dead spot"

-And yes, turbulance close to the intake sides of the blades causes noise in any radial fan. The blades work most efficiently, and quietly, when the airflow reaching them is as laminar as possible.



But really guys, this is not an issue worthy of getting worked up about. It's not religion, or "Why Mac's suck" :lol: (that's a joke, really, please don't go there)

If you can make it work for your situation....go for it! That's what really matters. Everyone's situation is different. Bluefront made beautiful use of Alpha's in some of his projects. Heck, even my old Desk-PC used a ducted exhaust CPU...a Zalman 6000Cu ducted to a 120mm L1A.

The only reason I so vigorous rebunked Pirata was because his initial rant was clearly that of someone who was still learning. I didn't want him, or any future forum wanderer to stumble upon that and and then leave thinking it to be true. It's all about spreading information...that's all. :lol:

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Post by bomba » Mon May 24, 2004 5:55 pm

Rusty075 wrote:-The CPU is the most heat sensitive of any part of the computer. Your mobo will be just as happy at 50° as it is at 40°.
Yes, but the hard disks may not be.
Rusty075 wrote:-Intake ducting the CPU only effects the PSU if you are using the PSU as a case exhaust...which you shouldn't be. As one of the other big heat producers, it should have its own supply of cold air.
Yes, but what Spydercat, Putz et al have been trying to say is that case temps will be close to ambient if you duct CPU exhaust out of the case, negating the need for a dedicated PSU duct. This assumes relatively low power components and vidcard OR artic cooling type exhaust ducted GPU cooler.
Rusty075 wrote:-A difference of 5-10° in the temp of the air blowing over the CPU will make a big difference in the airflow required to cool it. An example:

Say you've got a typical 70watt CPU and a typical SLK-800, with a typical L1A.

Duct in ambient air, at a temp of 25°, you can get a CPU temp of 53° by running your L1A at 7 volts. That's 14dBa....very quiet, even by our standards

Suck case air through it at 33°, and to get to a CPU temp of 53° you need to run your L1A at 12volts. That's 24dBa...louder than most of us here would consider acceptable.
I'm not convinced, if CPU exhaust is ducted out, case temp & thus CPU intake should be close to ambient with no intake ducting required.
Rusty075 wrote:It's all about the °C/W and the Delta T. And this example assumes the unrealistic hypothesis that the SLK would perform equally in both directions. As explained above, it won't, so in reality you've never be able to get to 53°
But what if an HT-101 style HSF is used instead? These HSF's may be configured in blow and still duct exhaust out of the case.
Rusty075 wrote:The only reason I so vigorous rebunked Pirata was because his initial rant was clearly that of someone who was still learning. I didn't want him, or any future forum wanderer to stumble upon that and and then leave thinking it to be true. It's all about spreading information...that's all. :lol:
Aren't we all still learning??? I know I am. As a moderator you should work harder to maintain composure and set an example for others...and I'm not so sure Pirata is incorrect, certainly Dell with their green CPU exhaust ducts and fanless CPU heat sinks tend to agree. Dells are known as quiet tho not to "SPCR standards" they are quite good for the low cost components they use.

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Post by Pirata » Mon May 24, 2004 6:45 pm

I certainly appreciate Rusty075's endeavour to enlight me. I am nothing but an "eternal newbie" as I use to say, and every bit of help is more than welcomed. With this said...

While Rusty075's arguments are plausible and most probably right, I have to disagree with him in one point: I would never state, nor insinuate, that persons around here are stupid. I also wouldn't define my initial post as a rant, but let's forget about it.

I agree with bomba that a moderator should stand above the rest with regard to serinityand patience. But I won't be teaching lessons here! :wink:

Let me have some rest to think all this over. I am really tired. Until tomorrow.

EDIT: for the time being, let me ask you something, Rusty075. If the mobo is so happy being baked at 50º, why does Intel's Active Monitor specify a max temp of 50º for the north bridge temp sensor of my D865PERL, and a max temp of 60º for the temp sensor on my P4 2.6GHz?

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Post by Rusty075 » Mon May 24, 2004 7:23 pm

bomba, pirata, clearly I'm been communicating poorly, and for that I apologize. (that's what I get for typing posts while at work....my thought process is all disjointed :roll: )

The whole point of this was to demonstrate that there isn't one way to do anything. Rereading it, it does come off as being "anti-sucking", instead of pro-"do-whatever-works-for-you", and that's my fault, for overcompensating for pirata's "enthusiasm" to the contrary.

But if you have a theory, I urge you to actually try it. Ducting the CPU exhaust out, in my experience, doesn't give you reduction in case temps that you're expecting. (mostly do to the fact that at SPCR speeds, you're actually exhausting a pretty small volume of air.) But try it, and report back! :lol:

And in that vein, I'm going to finish up the write-up of my current main system, it's got ducted intakes for both the CPU and the PSU, and no exhaust fan at all.

I'm the king of procrastination...so give it a few days. :wink:

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Post by TheWesson » Tue May 25, 2004 10:31 pm

@ 20 CFM thru the case and 50W in your case (not counting CPU and PS which is assumed to have its own ventilation) the rise in case temp (vs ambient) should be ~4C

That is about what I get.

With my Aeroflow there was 10-20% loss in HS efficiency when reversed.

So you pay 5-10C in CPU temps for ducting to exhaust and throwing away a case fan (as versus ducting from intake.)

Worth it? I guess it's sort of a tossup. It's certainly better than not ducting at all.

the wesson

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Post by Pirata » Wed May 26, 2004 3:13 pm

Hello again. Here is a "silent PC planning" that uses much of what has been discussed in this thread. I'd like to read your opinion on it.

An easy, yet expensive way to reduce noise even further is to buy a fanless PSU. I am an advocate of fanless PSUs. Of course I don't have empirical proof or user testimonies to judge upon, but I still really believe that the huge price you pay for those fanless units goes into extra-good build material and components, along with good design. Guarantee periods are 2 year in general, like any other fanned PSUs, so manufacturers are confident on these products. Experts like MikeC do not like them, because they say they fail more easily, mainly because of the high temperatures they develop... as I said, I think the money you pay for them goes precisely into solving that. Since a fanles PSU provides no airflow, I think they should be removed out of the case: since they are noiseless, there is no noise concern in doing so.

So the PSU fans goes missing in exchange for a lot of money. Noise floor is now conditioned by case fans and HDs.

Has anybody already tried to remove the HDs out of the case? It can be done if you are using SATA, since data cables are quite long. There are also ATX power cable extension, if they were needed. If you take HDs out, you'll surely need this:

http://silentmaxx.net/catalog/sm_hard_d ... losure.php

This HD enclosure must be the best around: no HD fans are needed, HDs are completely enclosed, and a rather big heatsink sits on top of them. In principle, you should get 0dBA, extended service life (because of reduced HD temperatures), and strong EMI shielding, so there should be no noise concern with this, neither. Oh! This is important: SilentMaxx's enclosures cost 50? a pop.

Well, if HDs are removed, there is less heat inside the case, and that's good. Also, seek/read/write noise are also out of the (sonic) picture, and the noise floor is determined only by the fans (of course, as silent PC freaks that we are, our northbridge is passively cooled, and so is our good-but-not-too-powerful VGA card).

Now we have the CPU, chipset and VGA as main heat sources, and it seems clear that hot air from the CPU could be also removed from the case with a sucking HS, which could allow us to make away with the case fans.

Here comes our little blow vs suck discussion again. Since arguments in favor and against have come from many corners, I'll try to wrap up my small conclussion.

If we use a sucking HS+ducting with the CPU, we get even more heat out of the case, making it easy for us to kiss goodbye the case fans, but that comes at a price: as Rusty has pointed out, sucking HSs are not as efficient as blowing ones, and you can see it in the SPCR HS top rank and reviews (though the new alphas have not been tested yet). There is also the fact that you're using hotter air to cool the CPU. Finally, if you take into account that ducting reduces a fan's airflow (and we won't be using any further fan in the duct exhaust), you can conclude that, in order to achieve equivalent cooling, you need higher rpms sucking than you do when blowing. Thus, the noise advantage of removing case fans could simply be not worth the effort.

On the contrary, ducting into the case fresh air and blowing it on the HS has allowed people around here to reduce CPU fan voltages to 7V, while keeping good temp levels in the core. This, even with the airflow restriction that a duct poses.

Well: the only solution I see, that combines the possiblity to use outside air to cool the CPU, while more or less keeping the ability to exhaust the hot air stream to the outside, is the use of a tower HS (e.g. Aerocool HT-101). So, you put a duct from one fan hole to the intake part of the HS, where a 7V Panaflo pushes air through the fins and heatpipes. The air gets through the HS, exits, and moves further towards the upper side of the case. There, it can be fastly exhausted through convection. The mobo and graphic card don't even touch it.

NOTE: in my current PC, the exhaust air of the CPU HS hits directly the northbridge HS. Of course, my northbridge temp sensor gets crazy about it. That's why I think it is important to be able to direct the hot air stream where it can be exhausted quickly.

The problems of this: I don't know how good tower HSs are when compared to the Swifttechs and Thermalrights. They have 6 heatpipes, so, damn, they should be really good at sucking heat out of the CPU. The fins and pipes are huge, so a small airflow should make a lot. And don't forget there is no dead-spot problem with this HS. In spite of all this, there is a point that worries me: tower HSs are far cheaper than the Swiftechs and Thermalrights. It could be nothing important, but price uses to be a measure of performance, which would mean that tower HSs are not that good after all.

Also there is the size problem: more than 500gr hanging perpendicularly of the mobo means the case has to be handled with care. Other HSs don't have this problem.

People, your turn. Do not be harsh. Be tender. I know that all this is just too obvious...


EDIT: we have also learnt here at SPCR, that 2 slow-spinning fans might do the work of one fast-spinning fan at lower noise levels. Could it be possible that two 5V-80mm panaflos mounted on the tower HS could make the job of a 7V-80mm at lower noise levels? And what about one single 5V-92mm panaflo instead of the 7V-80mm?

And one last thing: in the ducted tower HS + fan setup described above, do you guys think that removing the fan from the HS and screwing it as a case fan, then ducting it to the HS would do any harm to the airflow? (independently of the voltage used) I know noise would increase because of suck turbulence, but the weight supported by the mobo would decrease this way.

EDIT2: Jeeesus, I am forgetting radial cooling (Zalman 7000). Definitely a hot air spreader! We don't want that, do we?
Last edited by Pirata on Wed May 26, 2004 4:20 pm, edited 2 times in total.

MikeC
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Post by MikeC » Wed May 26, 2004 3:43 pm

Probably sound like an endless tape loop...

A fanless PSU would be fine if the efficiency was really high (>80%), it had lots of heat-radiant surface, and that surface could be exposed to the outside air. Also, you really want the case really customized for it so that the PSU is exposed to the hot air from other components.

But as a drop-in replacement in an ATX case, I have yet to see one that cuts it. There's just too much heat from other components for the PSU to cope with, IMO. And even with the extra $ into higher rated components, if there is nowhere for the heat to go, the thermal challenges are way too demanding. You can even cook a 10W drive by putting it in a position with no airflow at all; a PSU is often going to generate 40W in itself AND its position in the case ensures that it will probably deal with another 50% of the heat from the rest of the components.

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