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Old 05-01-2019, 06:09 AM
c-attack c-attack is online now
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Good, I am glad that’s sorted. In regard to the fans, it is a competition if you adjust the peak value numbers down to 1200 rpm or wherever you normally run. Most 140mm fans have P-Q curves linear enough to estimate effective airflow or static pressure at rpm X. The numbers are substantially similar at like speeds, except of course the ML “Quiet” that come with the Pro series are capped at 1200 rpm, thus the reference to “willing to run them faster”, which you do. I’ve had both the A14i and original 2000 rpm ML140 Pro fans for years and never found a performance difference, but did prefer one or the other in certain builds for aesthetic reasons. One thing about the ML bearing is it tends to make the fan a bit quieter in the middle rpm zone (700-1100 rpm for a 140mm) in comparison to SSO2 or other common FDB/rifle bearings. Since that is the range where most people spend the bulk of their time, you can see why they include them in this form and with the lower speed cap. I am not sure if you can remember what your stock H115i fans sound like, but I think this was a good direction to go for most people. Typically those that need high rpm fans already have them and have a definite preference on which ones they use.

The Pro series was also the first Corsair cooler with three fan speeds and specifically the Quiet 1100 rpm pump mode. Obviously there was a clear intent to make a quieter total package in comparison to the predecessor. In regard to the Quiet pump speed, it’s fine for sitting on the desktop doing light work, but you have too much CPU for that under load. Normally you don’t get much difference in coolant temp between pump speeds. The total length is short and the fluid resistance low in AIO packages. However, 1100 appears to be low enough to cause a relatively large drop in flow rate and you will notice the temp differences. Just FYI.

Last edited by c-attack; 05-01-2019 at 06:12 AM.
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Old 05-01-2019, 09:32 AM
Yanta Yanta is offline
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Say what? Almost all of that went straight over the top of my head.

I remember the SP140 fans - Loud in comparison to the Noctua's I'm using. IIRC I couldn't set them below 820 RPM. The Noctua's will go as low as 300 RPM.

I set my CPU fans to 1500 RPM at 75c. The curve is not linear. More like the bottom right side of a circle. At 20c the speed was set so the fan speeds run about 600rpm. I currently have them running around 575. Pretty quiet. I use them because the air flow and static pressure are very high, and they are quieter. At 1500RPM IIRC they are quieter than the SL140's. I forget what the SP140 max speeds were

Case fans: The 3 x P14S fans run faster @ 550-600 RPM because they are exhaust fans. The 7 S12B fans are intake and run at 400 minimum at 20c

So, with what you said above - are you saying I should not limit my CPU fans lower than their maximum values? I'm not following what you said.

I did notice that the CPU fan curve can't be set more than 60c which is insanely low when the curve is based on the CPU Package.

On Quiet the pump runs @ 1020 RPM. Balanced @ 2040 and Performance @ 2760 which is audible. I have it set at balanced.

Last edited by Yanta; 05-01-2019 at 09:34 AM.
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Old 05-01-2019, 07:06 PM
c-attack c-attack is online now
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Yeah, the SP140L are loud, I hate them, and thus this was likely part of the rationale to moving to a more civilized fan in the ML-Quiet. I would have put the A14i on the first day for your old H115i and in fact, that is exactly what I did.

Obviously airflow is dependent on fan speed, so a 140mm fan that moves 80 cfm at 2000 rpm will only move an estimated 40 cfm at 1000. In reality, the P-Q curve is not perfectly linear, but that is the best we can do without one. The same holds true for static pressure. Static pressure is the amount of negative pressure required to reduce a fan to a speed of zero. So the higher the RPM, the higher the static pressure. This does not directly equate into improved radiator performance. That little 40x40 fan that runs at 5000 rpm will have a staggering pressure rating, but still move a minuscule 11 cfm. Try that on your radiator. The ML140 Pro (2000 rpm max) I have in my hand right now rates at 100 cfm and 3.0 mm H20 at 2000 rpm. That is competitive with the like speed A14 industrial. The point I was making about is the ML140 Quiet is the same blade and frame and will move the same amount of air as the ML140 Pro when they are both at the same speed. The only limitation is the 1200 max speed and thus the remark about only needing it if you use it. At 700-900 rpm, all three are going be indistinguishable. At any rate, this was not a persuasive argument to switch your fans. Just don't toss the ML140-Quiets like you might the old SP140L. They have value. If you really want to see a ML vs A14i comparison across the RPM band, there are a few floating around the internet.

Yes, that is the general advice I give to others as well. Park the pump on Balanced and be done with it. You will (and should) be able to hear the Extreme 2850 rpm setting. My $200 D5 is certainly audible at 3000 rpm, even with a much more complicated dampening system. For most people, even with 200W+ HEDT CPUs, you won't see a coolant difference of more than 1C between the two higher speeds (2160/2850). You can certainly test that. If you are going to set a 30 minute render and leave the room, it hardly matters and can use it. If you have a lot of mixed use, put on balanced and leave it.

The cooler's fan controller was meant to use coolant temperature (H115i Pro Temp) as the control variable. If your coolant hits 60C, you have issues. In spite of this, Corsair has made CPU temp a control option and probably needs to adjust the graph scale to a more appropriate 80C+ to make reasonable data points. Since they have not, that is yet another reason to use coolant temperature as the control point. Remember, fans the pump speed have no effect on the electrical heat created under the CPU at the pins. The fans and pump do get rid of the waste heat conducted through CPU and cold plate. +1C coolant temp = +1 CPU temp. If the coolant is not going up during whatever you are doing, more fan or pump speed will not make it cooler. There is a definite minimum coolant temp you cannot get under. For most people that is ambient temp + 3-4C or most certainly case temp is you are top mounted.
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