I think it all depends on the usage. Fanswap in general might not be worth it, because it void warranty, but if you have a low power computer, you just might use the fan with an external fan controller (fan mate?) set to 5-7v.Khrono Devil wrote:I would have to say no, replacing a 1200rpm fan with a 2000rpm it just wouldn't cut it at the higher loads.Alex wrote:I take it my fanswap idea is feasable.
My Corsair HX520W is my loudest component...
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Yes but does the fan need to be spinning that fast when there's almost only the PSU heat to take care of. The PSU must have been designed for a normal case (take care of more heat) and not a 2 chamber case or is this wrong?Khrono Devil wrote:I would have to say no, replacing a 1200rpm fan with a 2000rpm it just wouldn't cut it at the higher loads. The adda fan speeds up to 1200rpm at about a 60% load @ 22 ambient on a workbench ( aka not in a case ).Alex wrote:I take it my fanswap idea is feasable.
But this is irrelevant according to you. I just want to now why?
Please tell me what I have missed or is it simply so that the PSU will be to hot at >60% load despite it's in a separate chamber? Will a 1600 rpm fan be enough to handle say 150W or should it be a 2000 rpm one?
As an example say that the PSU has 80% efficiency. Then 600 W/0.8 = 750W will be fed to it. => 150 will be lost in PSU.
If the fan had to take care of all the case heat (in a normal 1 chamber case not my P180B) it would have to take care of all 750W right?
So considering the 2 chamber it should be enough if the fan takes care of 150W of 750 W (=20%) of what the PSU is designed for.
But still this seems to be wrong according to you or will a 1200 rpm fan not have 20% of 2000 rpm fan airflow?
What is wrong with this? Please help me and probably others to understand? I will gladly listen and learn from your experience/thoughts about this.
I will not use the PSU for more than about 200 W draw (I should have bought a smaller one) but still I would like it to be OK with up to 400 W Load (=margin).
It's not clear what you're saying here, but the PSU is not designed to get rid of all the case heat, the designers expect the case fans to do that.If the fan had to take care of all the case heat (in a normal 1 chamber case not my P180B) it would have to take care of all 750W right?
So considering the 2 chamber it should be enough if the fan takes care of 150W of 750 W (=20%) of what the PSU is designed for.
two identical fans, one at 1.2krpm the other at 2krpm, the 1.2krpm will delivery roughly 60% of the airflow of the 2krpm in free air. In a psu the air resistance means the airflow will be less in both examples.will a 1200 rpm fan not have 20% of 2000 rpm fan airflow?
The original Adda is a 2200rpm fan rated for 85cfm. The problem with swapping for a 1200rpm fan (and using the psu's fan controller) is that until >300W fan control circuit only provides <3.9V; it is very likely the 1200rpm fan will not start at this voltage.I guess the original Adda is a 1600 rpm fan but in the lower bay there is no mobo (CPU, GPU) heat to take care of so it should be OK to swap for a 1200 rpm fan (Such as S-Flex D) instead.
you should just put a 1200rpm fan on a fanmate and set it where you cannot hear it but still producing a decent amount of airflow.
Now I'm with you 100%.
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Khrono Devil
- Posts: 38
- Joined: Sat Jun 02, 2007 2:18 am
- Location: New Zealand
1200rpm @ around 60% load @ 22C ambient on a test bench. Its getting more fresh air than what it can handle, putting it in a case would restrict its air flow. Also the ambient inside the case would be higher than open air.
As the heat builds up inside the PSU its total output and efficiency decrease, up to 60% load it would most likely be perfectly fine with a 1200rpm fan.
Like I said in my earlier post - "replacing a 2000rpm fan with a 1200rpm it just wouldn't cut it at the higher loads". (edit typo)
I never said anything about it not handling loads below 60%, I was just trying to warn you so that you don't end up destroying a perfectly good PSU by putting to much load on it than what it can cool.
I don't think you realize just how much 150W of heat is, a typical CPU uses under 80W and that can easily load up to 60C with stock heat sinks.
Ok so that doesn't sound very good but basically not all of the Watts that your computer uses is not converted to heat.
As the heat builds up inside the PSU its total output and efficiency decrease, up to 60% load it would most likely be perfectly fine with a 1200rpm fan.
Like I said in my earlier post - "replacing a 2000rpm fan with a 1200rpm it just wouldn't cut it at the higher loads". (edit typo)
I never said anything about it not handling loads below 60%, I was just trying to warn you so that you don't end up destroying a perfectly good PSU by putting to much load on it than what it can cool.
I don't think you realize just how much 150W of heat is, a typical CPU uses under 80W and that can easily load up to 60C with stock heat sinks.
The PSU doesn't deal with 750W of heat when placed in a normal ATX case. If a PC outputted 750W of heat you could use it as a heater, just because a piece of hardware uses so much power it doesn't mean that all that power is then lost as heat. Most of the power is lost/used in the working of the transistors and heat is caused by the friction and current leakage inside the transistors/CPU.As an example say that the PSU has 80% efficiency. Then 600 W/0.8 = 750W will be fed to it. => 150 will be lost in PSU.
If the fan had to take care of all the case heat (in a normal 1 chamber case not my P180B) it would have to take care of all 750W right?
So considering the 2 chamber it should be enough if the fan takes care of 150W of 750 W (=20%) of what the PSU is designed for.
But still this seems to be wrong according to you or will a 1200 rpm fan not have 20% of 2000 rpm fan airflow?
What is wrong with this? Please help me and probably others to understand? I will gladly listen and learn from your experience/thoughts about this
Ok so that doesn't sound very good but basically not all of the Watts that your computer uses is not converted to heat.
Last edited by Khrono Devil on Sat Jun 09, 2007 4:54 am, edited 1 time in total.
OK. Yes as you say this might work. As I understand it from your comments there is probably no margin then though.Khrono Devil wrote:As the heat builds up inside the PSU its total output and efficiency decrease, up to 60% load it would most likely be perfectly fine with a 1200rpm fan.
Yes you are right. Thank you for warning me. I got the message 100%.Khrono Devil wrote:I never said anything about it not handling loads below 60%, I was just trying to warn you so that you don't end up destroying a perfectly good PSU by putting to much load on it than what it can cool.
Actually I reacted to this myself. Wanted to go through with my initial thoughts though. I think 2200 rpm fan might handle 150 W (with very hot components) but certainly not 750 W for sure.Khrono Devil wrote:I don't think you realize just how much 150W of heat is, a typical CPU uses under 80W and that can easily load up to 60C with stock heat sinks.
Well I agree that for example a very small amount of energy is converted to light in light diodes and some is transfered to air flow by the fans but most of the energy is normally finally converted to heat like through resistances in circuits or motor friction.Khrono Devil wrote:The PSU doesn't deal with 750W of heat when placed in a normal ATX case. If a PC outputted 750W of heat you could use it as a heater, just because a piece of hardware uses so much power it doesn't mean that all that power is then lost as heat. Most of the power is lost/used in the working of the transistors and heat is caused by the friction and current leakage inside the transistors/CPU.
Ok so that doesn't sound very good but basically not all of the Watts that your computer uses is not converted to heat.
In digital circuits (transistors) the energy is temporarily stored in "capacitors" (also MOS transistors and electrical lines have "parasitic capacitances"). When these "capacitors" are uncharged all their energy is normally converted to heat. This happens when short circuiting (switching) to ground.
As transistors and capacitors do have resistance when switching and ground leads are not superconductive the energy is converted to heat through these resistances. Of course there are some resistive heat losses during capacitor (up) charge switching also.
It is possible to store a part of the capacitively stored energy for reuse in other energy storage capacitors or batteries but the discharging time gets severely decreased then, so this is normally only done in slower low power circuits that rarely is used in desktop computers yet.
Also the low power circuits have to have a more complex design (=more expensive and longer time to market). This will come in the future with the help of more advanced design tools and cheaper chip area manufacturing (denser chips / More's Law). I don't think we are there yet for our desktop CPUs and surrounding circuits but this is possibly true for laptops already?
This might be interesting: http://silentpcreview.com/forums/viewto ... ht=#334430
My Corsair HX520 was virtually inaudible when I first got it (late January), but has recently gotten quite a bit louder. It also seems to have developed a MINOR case of coil whine. Compared to the first HX520 I got (defective unit with ridiculous coil whine) this is nothing. Still enough to cause annoyance, unfortunately. I'm looking to do either a fanswap, or get a passive PSU.
My Corsair HX520 was virtually inaudible when I first got it (late January), but has recently gotten quite a bit louder. It also seems to have developed a MINOR case of coil whine. Compared to the first HX520 I got (defective unit with ridiculous coil whine) this is nothing. Still enough to cause annoyance, unfortunately. I'm looking to do either a fanswap, or get a passive PSU.