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@ Corsair engineers: is Corsair RMi fan triggered by load, temperature, or both?


corsican
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question's in the title

 

since wattage is easier to measure reliably & accurately than temperature I reckon the trigger would be wattage-based (also the fan curve on user instruction on website page suggests it's load-based)

 

but then what if PSU overheats even on low load? (eg. in a small poorly cooled case or w/e) then a thermal trigger would also be useful

 

so which of the two is it? or is it both?

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  • 3 weeks later...
Based on a certain temperature threshold.

ok but in that case the user guide pdf should be edited cause they give the wrong info:

 

https://www.corsair.com/corsairmedia/sys_master/productcontent/RMi_Manual.pdf

 

they say the fan curves depend on wattage (in fact it says the fan curve even depends on each model for instance in the RM850i it says it requires higher wattage for fan to trigger than in the RM750i)

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  • 4 weeks later...
  • Corsair Employees

Hi Corsican, as stated in the manual and as you pointed out, the fans are actuated with the load on the PSU. The reason it's higher on the RM850 is because the load at which the fan actuates is a percentage (40%) of the max power output.

 

RM1000i -> Fan actuates at 1000W*(0.4) = 400W

RM850i -> Fan actuates at 850W*(0.4) = 340W

RM750i -> Fan actuates at 750W*(0.4) = 300W

Edited by Corsair Kevin
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i guess no wonder my HX1000 all the time very hot to the touch, because my pc roughly i guess pulling around 360w more or less...didn't reach the 40% load of the PSU the fan never turn on before..

 

You may want to consider a lower wattage PSU for your needs. Peak efficiency is going to hover around 50% load or just under. The HX750 would probably be better unless you plan on adding another GPU in the very near future.

 

Please refer to the HX series manual for efficiency graphs here:

https://www.corsair.com/corsairmedia/sys_master/productcontent/HX_Manual.pdf

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Based on a certain temperature threshold.

 

the fans are actuated with the load on the PSU.
alrite now this is confusing :bigeyes:

 

so to be really 100% sure this time is it load or temp or both?

 

(logic would say it would be both because, what if PSU somehow overheats despite a low load? or conversely what if PSU's on heavy load but the thermal sensor - which tends to be inherently less reliable than load sensor - does not trigger?)

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alrite now this is confusing :bigeyes:

 

so to be really 100% sure this time is it load or temp or both?

 

(logic would say it would be both because, what if PSU somehow overheats despite a low load? or conversely what if PSU's on heavy load but the thermal sensor - which tends to be inherently less reliable than load sensor - does not trigger?)

 

 

Fan actuation is based on load.

 

Your concerns are definitely a reality, which is why the PSUs have over-temp protection -- essentially the PSU shutting down. I can't stress enough that buying a PSU isn't just something to take lightly, which is why we show both efficiency and fan curves in the manuals.

 

It's important to always calculate or even estimate minimum, maximum, and estimated average power draw BEFORE you build your system so you can accurately decide on a PSU. You'll notice that peak efficiency is around 50% load on our PSUs, with a little variance between models/series.

 

e.g. If you're only drawing 300W, it doesn't make sense to have a 1200W PSU.

 

As for temperature sensing being inaccurate, variance is relatively small on temperature sensors.

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Fan actuation is based on load.

 

Your concerns are definitely a reality, which is why the PSUs have over-temp protection -- essentially the PSU shutting down. I can't stress enough that buying a PSU isn't just something to take lightly, which is why we show both efficiency and fan curves in the manuals.

 

It's important to always calculate or even estimate minimum, maximum, and estimated average power draw BEFORE you build your system so you can accurately decide on a PSU. You'll notice that peak efficiency is around 50% load on our PSUs, with a little variance between models/series.

 

e.g. If you're only drawing 300W, it doesn't make sense to have a 1200W PSU.

 

As for temperature sensing being inaccurate, variance is relatively small on temperature sensors.

so basically fan is controlled by load only, however there's also a temperature sensor (for OTP)? good to hear

 

at what temp does OTP trigger?

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so basically fan is controlled by load only, however there's also a temperature sensor (for OTP)? good to hear

 

at what temp does OTP trigger?

 

 

Our PSUs have multiple thermistors located near critical components, and the PSUs are rated [and tested] up to 50C.

 

Some of the models, such as the RMi, also have a temperature trigger for the fan, but primary actuation is based on load.

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I want to add to what I mentioned in that last reply. The temperature trigger, while it exists, is more of a contingency if there's a rapid spike in temperature. There's basically no fan curve, as the fan immediately ramps up to 100% as an attempt to rapidly cool any components that may be getting excessively hot. If this doesn't work, the OTP activates and the PSU powers down.
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wait so the RMi does have dual trigger (both load and temp based) for the fan?

 

Yes, but again, it's only when temperatures are at critical levels and should, in my personal opinion, only be considered a contingency trigger, not something most people would see under normal or even heavy use.

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