Corsair CX750m noise

jonadam23

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I have a corsair cx750m and its fan is noticeably the loudest component in my system. Its a low-pitched humming sound with a little bit of a whining noise to it. I'm definitely not overloading the PSU (I have a 65w tdp CPU with a r9 270x and a single hdd) so I am guessing this is just how the psu sounds. Would it make more sense for me to buy a fanless psu or are there quieter options.
 
Power supplies are designed to function when the computer goes into a sleep state.
These sleep states use much less power than any computer components can even at idle.
You can never strain a power supply by using one that is rated higher than you need.

Haswell CPUs do support some new sleep states that some power supplies can't handle. It doesn't strain the power supply, but you may need to turn it off with the switch on the power supply and back on again if the system goes into these states. These can easily be disabled in the BIOS if you do not have Haswell certified power supply.

Efficiency for an 80 plus power supply is measured at 20%, 50% and 80% load. This means that the power supply does not have to meet 80% efficiency below 20% load or above 80% load. Efficiency drops off gradually below 20%, but remember that you are drawing less power anyway so it makes very little difference. If your system is drawing 30W, at 80% efficiency this draws 37.5W at the wall or at 70% efficiency it draws 42.9W at the wall.

As for noise, you have two cases. Noise at idle and noise at load.
The system in this case will draw about 30W at idle and up to 285W at load.
When picking a power supply, keep the total draw under 60% at load if you want the supply to stay quiet at load.
At idle the load will be low anyway.
Given how low these numbers are, we can cover both cases with a 500W supply.
There is nothing wrong with using a higher power supply except cost. I would however consider this a factor because you can get a much better quality supply with a lower rating for the same price.

Typically fan noise at low load will be a lower pitch, but it can be very annoying from a bad fan.
At higher load the fan noise will tend to be higher pitched.
You can also get component noise at any load.
You can get fanless models but they are very expensive and not really worth it.
Better to just get a supply with a quiet fan. A hybrid model that stops the fan at low load is a nice added extra but not really necessary if the fan is quiet anyway.

If looking at Corsair:
The RM series are their hybrid models where the fan does not run at low load. RM 450 / 550 and 650 are good. THe RM 750 and 850 are from a different manufacturer and should be avoided.
The HX series are just better quality in general and very quiet.

The Seasonic X series are hybrid models and fantastic quality, but expensive.
The EVGA Supernova G2 750 is great quality too and I haven't heard any complaints about noise, although I haven't read a review specifically on noise for this supply.
If looking for reviews on noise, look at www.silentpcreview.com.
If looking at reviews on quality, look at www.jonnyguru.com.

Most likely, if you get a top quality model 500W or higher, you won't have any problems.
This list can be useful too, stick to tier 1 or tier 2 class A if looking for a top quality model:
http://www.tomshardware.com/answers/id-1804779/power-supply-unit-tier-list.html

 

Videographer

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I would get a hybrid or a fan model with a good reputation for being quiet - the fans were put in for a reason and benefit other components too. Look for 80+ bronze or gold supplies

Just to check, are you sure it is the fan and not also high pitched coil whine?
 

Videographer

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Also if you're buying a new supply anyway, get a smaller one. That system under a normal load ie on the desktop or word etc won't draw much, probably 50-100W with a max tdp of about 250W which you won't ever hit unless you run some insane benchmarks or torture tests.

Power supplies are desgined for something like 40-90% load using such little of you 750W supply is not only inefficient it terms of power usage it also puts a strain on the components. If you want headroom for upgrades a 500w would support a 95w CPU and the latest nvidia gpus. 750w would be for extreme overclocking of high tdp parts or for a low end sli system. 500w 80+ PSU will do better than a 750w one in your current system
 


I don't believe it "puts a strain" on the PSU to deliver low loads, it only adversely affects the efficiency of the PSU.

 

Videographer

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It will do, you're running all those transformers out of spec making it harder to keep voltages stable. Just like asking for too much power it can do it but its not designed to do it well.

Whether it would shorten its life beyond normal expectations I don't know, good PSUs don't go bad very often, they seem to fail either very quicklyquickly due to poor quality or after many years due to use so I doubt there is a decent benchmark

Imagine running a motor at a too low voltage for a long time - it will damage it. Its not the same but its still coils and electricity and not putting enough amps through to maintain voltages could damage components inside like regulators (obviously you won't melt a coil or trip a fuse like pulling too much power could)
 

Darkbreeze

Retired Mod


Having too big a PSU will not adversely affect the system. It will certainly decrease efficiency, but it's not going to hurt your hardware. It it was problematic, not only would hardware come with minimum PSU requirements like they do, PSUs would come with minimum demand requirements as well.
 

Videographer

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Recommendations wise I would go for a seasonic s12-g450 or a xfx ts GOLD 550 if you can find it and want the higher wattage

Remember high efficiency means less watts converted to heat and sound leading lower system noise. 750w at 75w will produce more heat that a similar quality 350w at 75w but will probably have bigger heatsinks and fan to deal with it
 

Darkbreeze

Retired Mod
Power supplies are designed to function when the computer goes into a sleep state.
These sleep states use much less power than any computer components can even at idle.
You can never strain a power supply by using one that is rated higher than you need.

Haswell CPUs do support some new sleep states that some power supplies can't handle. It doesn't strain the power supply, but you may need to turn it off with the switch on the power supply and back on again if the system goes into these states. These can easily be disabled in the BIOS if you do not have Haswell certified power supply.

Efficiency for an 80 plus power supply is measured at 20%, 50% and 80% load. This means that the power supply does not have to meet 80% efficiency below 20% load or above 80% load. Efficiency drops off gradually below 20%, but remember that you are drawing less power anyway so it makes very little difference. If your system is drawing 30W, at 80% efficiency this draws 37.5W at the wall or at 70% efficiency it draws 42.9W at the wall.

As for noise, you have two cases. Noise at idle and noise at load.
The system in this case will draw about 30W at idle and up to 285W at load.
When picking a power supply, keep the total draw under 60% at load if you want the supply to stay quiet at load.
At idle the load will be low anyway.
Given how low these numbers are, we can cover both cases with a 500W supply.
There is nothing wrong with using a higher power supply except cost. I would however consider this a factor because you can get a much better quality supply with a lower rating for the same price.

Typically fan noise at low load will be a lower pitch, but it can be very annoying from a bad fan.
At higher load the fan noise will tend to be higher pitched.
You can also get component noise at any load.
You can get fanless models but they are very expensive and not really worth it.
Better to just get a supply with a quiet fan. A hybrid model that stops the fan at low load is a nice added extra but not really necessary if the fan is quiet anyway.

If looking at Corsair:
The RM series are their hybrid models where the fan does not run at low load. RM 450 / 550 and 650 are good. THe RM 750 and 850 are from a different manufacturer and should be avoided.
The HX series are just better quality in general and very quiet.

The Seasonic X series are hybrid models and fantastic quality, but expensive.
The EVGA Supernova G2 750 is great quality too and I haven't heard any complaints about noise, although I haven't read a review specifically on noise for this supply.
If looking for reviews on noise, look at www.silentpcreview.com.
If looking at reviews on quality, look at www.jonnyguru.com.

Most likely, if you get a top quality model 500W or higher, you won't have any problems.
This list can be useful too, stick to tier 1 or tier 2 class A if looking for a top quality model:
http://www.tomshardware.com/answers/id-1804779/power-supply-unit-tier-list.html

 

jonadam23

Honorable
Oct 20, 2013
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Thanks for all the help guys! I knew 750W was overkill but that was the only PSU my local Best Buy had a the time. I will definitely look into the PSU's that were mentioned and I sell my CX750M on ebay. I really appreciate all the help!
 

Darkbreeze

Retired Mod
You know, that unit shouldn't be noisy except under high loads. If it's noticeably louder than the rest of the system at idle loads, there is a problem with the bearings or something else internal. It should only be noticeably noisy during peak demand. If you do purchase another unit, go with a Tier 1, 2A or 2B unit and you probably won't have that issue. Tier 3 units are tier 3 for a reason. That reason being they are not as high quality and have a higher failure rate and are more problematic than higher quality units.
 


If that is the case, then depending on the age of the unit, OP might have a warranty claim?
 
D

Deleted member 217926

Guest


There are actually units in tier 2 only due to using a lower quality fan while being excellent electrically. The Seasonic G series stands out. It's every bit as good with regulation, ripple and noise as the X series it just uses a lower end fan. As such since tier 1 is reserved for the absolute best of the best it has to go in tier 2.
 

Darkbreeze

Retired Mod

I would think so. It would need to definitely be the PSU the noise is coming from and it would need to definitely be abnormal, but yes, if it's still under warranty I would think a noisy fan would be just cause for an RMA.
 

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