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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Mon Apr 11, 2011 6:52 am 
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quest_for_silence wrote:
steviewonders wrote:
That's the plan anyway. Just checking compatibility for the cooler i want and then i'm gonna combine it with an Enermax PWM fan with a manufacturer rating of as little as 8dBA. As the heatsink will be greatly reducing the heat of the CPU alone, the fan will only run at a low power and everything will still be kept cool at a low noise level.

Which Enermax PWM fan?


The Enermax T.B. Silence PWM. It looks pretty cool as well.

http://www.enermax.co.uk/products/fans/ ... e-pwm.html


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Mon Apr 11, 2011 8:57 am 
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steviewonders wrote:
The Enermax T.B. Silence PWM. It looks pretty cool as well.
http://www.enermax.co.uk/products/fans/ ... e-pwm.html
Enermax fans are always neat. I can't help but be attracted to them. But in terms of performance they have a mixed reputation. You might want to look at the plain jane Scythe PWMs. They aren't as fancy with all the technology... but they have a reputation of delivering good performance.

PS: dB readings vary so much from tester to tester, you can't compare them except when they all come from the same tester using the same methodology. I wouldn't rely on a manufacturer's reported dB results except to compare fans within their own line. Many people won't even go that far. I would look at SPCR's old test of enermax fans then look around these forums. There was a recent thread where Enermax fans were brought up and discussed.

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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Mon Apr 11, 2011 9:35 am 
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ces wrote:
steviewonders wrote:
The Enermax T.B. Silence PWM. It looks pretty cool as well.
http://www.enermax.co.uk/products/fans/ ... e-pwm.html
Enermax fans are always neat. I can't help but be attracted to them. But in terms of performance they have a mixed reputation. You might want to look at the plain jane Scythe PWMs. They aren't as fancy with all the technology... but they have a reputation of delivering good performance.

PS: dB readings vary so much from tester to tester, you can't compare them except when they all come from the same tester using the same methodology. I wouldn't rely on a manufacturer's reported dB results except to compare fans within their own line. Many people won't even go that far. I would look at SPCR's old test of enermax fans then look around these forums. There was a recent thread where Enermax fans were brought up and discussed.


Hmm. My search continues then. I always do a lot of research before i buy something. Ensures i get the best product and it adds to the fun. I'd like a fan that provides good air flow but noise is more of a concern for me as the massive cpu heatsink will compensate. I managed to find a comparison of 35 case fans here.

http://www.madshrimps.be/articles/artic ... z1IIV5UE3D

It only compares two PWM fans and the Scythe one does reasonably well. Fans are pretty cheap though so i want the best.


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Mon Apr 11, 2011 10:29 am 
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steviewonders wrote:
quest_for_silence wrote:
steviewonders wrote:
That's the plan anyway. Just checking compatibility for the cooler i want and then i'm gonna combine it with an Enermax PWM fan with a manufacturer rating of as little as 8dBA. As the heatsink will be greatly reducing the heat of the CPU alone, the fan will only run at a low power and everything will still be kept cool at a low noise level.

Which Enermax PWM fan?


The Enermax T.B. Silence PWM. It looks pretty cool as well.

http://www.enermax.co.uk/products/fans/ ... e-pwm.html

I have a couple of Cluster, which is nearly identical (HALO, Batwing, Twister bearing, 8dBA), just a tad slower (so quieter).
Even if they are more than decent, IME they are not preferable to all the Scythe PWMs (or - probably - to some expensive beQuiet! or Noise Blocker), at least with reference to sound/noise: as high pitched fans, mostly sound quality is a bit questionable, less smooth than Scythes, and those 8dBA are a pure invention. On a heatsink IME they're roughly equivalent to the famous 120mm Noctuas (not PWM, of course), but noticeably less expensive, and they should be preferred over a Slipstream just for horizontal mounting.

Eventually I wouldn't use an Enermax to aid a passive (ok, no more) CPU cooler.

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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Mon Apr 11, 2011 11:04 am 
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Quote:
I have a couple of Cluster, which is nearly identical (HALO, Batwing, Twister bearing, 8dBA), just a tad slower (so quieter).
Even if they are more than decent, IME they are not preferable to all the Scythe PWMs (or - probably - to some expensive beQuiet! or Noise Blocker), at least with reference to sound/noise: as high pitched fans, mostly sound quality is a bit questionable, less smooth than Scythes, and those 8dBA are a pure invention. On a heatsink IME they're roughly equivalent to the famous 120mm Noctuas (not PWM, of course), but noticeably less expensive, and they should be preferred over a Slipstream just for horizontal mounting.

Eventually I wouldn't use an Enermax to aid a passive (ok, no more) CPU cooler.


I was actually looking at the Be Quiet! Silentwings PWM just a minute ago. Seems to be pretty quiet. Found another fan comparison here.

http://www.xbitlabs.com/articles/cooler ... html#sect0


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Fri Jul 01, 2011 8:17 am 
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MikeC wrote:
The usual solution is to increase the airflow from case fans, which then increases the noise -- which then negates the whole point of running the CPU HS w/o a fan.


I don't agree it has to negate the point. My experience is that case fans causes less resonance than CPU fans.


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Thu Jul 28, 2011 4:43 pm 
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One thing I noted testing my TX-3 CPU cooler is that at a certain point you can throw a ton of air at a processor cooler and get very little back in regards to lower temps. I can lose only a few degrees off the temperature running at full speed with my 92mm Noctua v having it run at just over 1000rpm (which effectively makes it very quiet at that speed)

Thus..it's fairly easy to get a quiet/low level of noise by using oversized heatsinks with modest/lower levels of airflow over them.


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Mon Aug 22, 2011 12:40 am 
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I think that would be valuable because very few people have as much experience as you do about how mainstream desktop gear copes with low airflow. 8)


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Tue Aug 23, 2011 3:44 am 
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Well a lot of this is open to debate. And some people have their own ideas on things..
So it's not for me to tell anyone anything but I simply give my own personal view right or wrong :lol:

There are a lot of variations different fans have varying airfow, static pressure, ambient temps etc etc.

I will say one things straight off though I very strongly disagree with the modern thinking of bottom mounted PSU's. This IMO has a "negative" impact on airflow. A bottom PSU will draw cool air out of the system as it's placed low down (unless the fan is sucking in from the bottom of the case outside) if it's reversed inside the case it simply helps to take cooler air out which is counter productive to overall system temperatures.


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Tue Aug 23, 2011 4:21 am 
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Mr Spocko wrote:
A bottom PSU will draw cool air out of the system as it's placed low down (unless the fan is sucking in from the bottom of the case outside) if it's reversed inside the case it simply helps to take cooler air out which is counter productive to overall system temperatures.


Any air that's being exhausted out of the case must (and will) be replaced by "new" air being sucked into the case. So if the PSU exhausts cool air from the bottom of the case, new cool air will be sucked in from whereever that case gets its outside air.

A bottom reversed PSU might disturb the airflow setup of a case by drawing hot air to the bottom instead of letting it rise. But then again I don't think these things matter too much in a PC case.


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Tue Aug 23, 2011 7:21 am 
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Mr Spocko wrote:
...I very strongly disagree with the modern thinking of bottom mounted PSU's. This IMO has a "negative" impact on airflow. A bottom PSU will draw cool air out of the system as it's placed low down (unless the fan is sucking in from the bottom of the case outside) if it's reversed inside the case it simply helps to take cooler air out which is counter productive to overall system temperatures.

You overestimate the role of convection in a PC case that uses fans. A single slow spinning 120mm fan easily counters any rising heat due to convection. Besides, if the intake fan of a bottom PSU is facing up, it could have a role in evacuating heat from the video card(s), which would be fairly close -- within say 5 PCI slot distance, given the 2-3 slots vidcards occupy these days.

In contrast, there is little doubt that the top mounted PSU...
- always runs hotter, as the primary path of heat evacuation is via the case back panel exhaust fan directly below it. The additional heat, in combination with the low fan speed utilized in quiet PSUs, has the potential of shortening PSU life. I have personally seen several quiet PSUs which failed due to heat damage in cases where the PSU was mounted traditionally. Since a bottom mounted PSU is not subject to the heat from the rest of the PC components, it runs cooler, so longevity is improved.
- blocks the possibility of a top mounted vent above the CPU area to increase heat evacuation

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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Wed Sep 07, 2011 12:56 am 
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MikeC wrote:
Mr Spocko wrote:
...I very strongly disagree with the modern thinking of bottom mounted PSU's. This IMO has a "negative" impact on airflow. A bottom PSU will draw cool air out of the system as it's placed low down (unless the fan is sucking in from the bottom of the case outside) if it's reversed inside the case it simply helps to take cooler air out which is counter productive to overall system temperatures.

You overestimate the role of convection in a PC case that uses fans. A single slow spinning 120mm fan easily counters any rising heat due to convection. Besides, if the intake fan of a bottom PSU is facing up, it could have a role in evacuating heat from the video card(s), which would be fairly close -- within say 5 PCI slot distance, given the 2-3 slots vidcards occupy these days.

In contrast, there is little doubt that the top mounted PSU...
- always runs hotter, as the primary path of heat evacuation is via the case back panel exhaust fan directly below it. The additional heat, in combination with the low fan speed utilized in quiet PSUs, has the potential of shortening PSU life. I have personally seen several quiet PSUs which failed due to heat damage in cases where the PSU was mounted traditionally. Since a bottom mounted PSU is not subject to the heat from the rest of the PC components, it runs cooler, so longevity is improved.
- blocks the possibility of a top mounted vent above the CPU area to increase heat evacuation


So the Solo II is a big fail with a top mounted PSU? Something have to be right about it otherwise the Antec engineers would have choosen a bottom PSU in it's design?

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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Wed Sep 07, 2011 3:28 am 
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christianh wrote:
So the Solo II is a big fail with a top mounted PSU?

With reference to any top mounted PSU-style enclosure, it's just a drawback, not a major fail.
IMO, in most of not-gaming scenarios, probably it would be slightly noticeable, if not at all.

Summarizing, with such a case you have just to carefully choose the parts (so personally I wouldn't use a 730W ASUS Mars 2 in a Solo).

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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Wed Sep 07, 2011 8:49 am 
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christianh wrote:
So the Solo II is a big fail with a top mounted PSU? Something have to be right about it otherwise the Antec engineers would have choosen a bottom PSU in it's design?

You put words in my mouth -- I never said anything like "big fail". What I did say, essentially, is that the bottom mounted PSU case has significant advantages. One advantage the SoloII might have is with a fanless PSU. The top vent allows the heat from something like a Seasonic X fanless or Kingwin fanless platinum PSU to dissipate easily out of the case.

As for why Antec or any other case makers choose any design, I assure you, functionality & efficiency are NOT always top priorities. Cost, ease of manufacturing, marketability, etc usually take precedence, along with whatever the micromanaging big boss might want in the product. :lol: In the Solo2, it is clear the basic chassis foundation is unchanged from the original. It is the same chassis under the skin of many Antec (and probably other brand) midtower cases sold in the past... decade, I'd guess. Why? Avoidance of tooling cost.

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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Fri Aug 02, 2013 10:53 am 
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CA_Steve wrote:

If you want to have fun with capacitor lifetime calculations, here's a calculator @ Vishay for tantalums.



Whoa... Thanks. Very helpful information.


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Fri Aug 02, 2013 11:26 am 
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MikeC wrote:
Is Passive CPU Cooling Best for Silent Computing?

2. Does the CPU HS fan only cool the CPU? The fan on a CPU heatsink has the task of cooling not only the CPU but also important components on the motherboard such as the NorthBridge chip and the Voltage Regulator Module (VRM) which powers the CPU and sometimes other components as well. Motherboard manufacturers assume a certain amount of airflow from the CPU HS fan in their thermal design. Eliminating the CPU fan -- even with a massive, low-airflow-optimized heatsink -- usually means that those motherboard components will run a lot hotter. This can lead to instability and shorten the motherboard's liefspan. The usual solution is to increase the airflow from case fans, which then increases the noise -- which then negates the whole point of running the CPU HS w/o a fan.


Mike,

I am curious if you think this still true in the case of a tower heatsink. Assuming a fairly typical build with a tower heatsink blowing straight into an exhaust fan. Does the tower heatsink fan actually have any contribution to motherboard temperature?


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 Post subject: Re: Is Passive CPU Cooling Best for Silent Computing?
PostPosted: Tue Aug 06, 2013 6:54 am 
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Blood wrote:
Mike,

I am curious if you think this still true in the case of a tower heatsink. Assuming a fairly typical build with a tower heatsink blowing straight into an exhaust fan. Does the tower heatsink fan actually have any contribution to motherboard temperature?

Yes. The airflow from a fan on a typical tower heatsink is turbulent around the fins, which causes some of the flow to swirl a bit, and reach the board itself. This is not much airflow when the fan is spinning really slowly, but even a bit of airflow is still better than none.

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