PSU efficiency

[Hamster Homie]

Hey, so I have a Corsair CX550M power supply. When I look at HWMonitor I see my CPU only pumping 12W at idle and my GPU 5W. I have a couple LED things such as an AIO, RAM and 1 fan but I don't think this sucks up much power. What I don't know is how much my motherboard and my cooling devices are taking. Now, looking at the efficiency curve of my PSU ( http://members.cybenetics.report:5050/d/cybenetics_CUj_eu.pdf ), it's pretty bad before hitting 100W. Is a lot of energy being wasted or is it ok if my PC has such low wattages at idle ?

[RollinLower]

it's fine, there won't be anything that could get damaged or something. it's just as you said, on lower loads the efficiency of most PSUs drops. and more power will be lost to conversion and heat instead of actually powering the system.

this will still be very low amounts of power though.

[Eighjan]

27 minutes ago, Hamster Homie said:

Hey, so I have a Corsair CX550M power supply. When I look at HWMonitor I see my CPU only pumping 12W at idle and my GPU 5W. I have a couple LED things such as an AIO, RAM and 1 fan but I don't think this sucks up much power. What I don't know is how much my motherboard and my cooling devices are taking. Now, looking at the efficiency curve of my PSU ( http://members.cybenetics.report:5050/d/cybenetics_CUj_eu.pdf ), it's pretty bad before hitting 100W. Is a lot of energy being wasted or is it ok if my PC has such low wattages at idle ?

Just had a quick look in my "always on HWINFO64" and my 3600 & Vega 56 are using about 40W while on a browser session; if that's what your seeing, then you're fine.  What CPU/graphics combination are you using?

The only sensor I have active are Voltages, Fan Speeds & Powers...

[Eighjan]

1 minute ago, RollinLower said:

it's just as you said, on lower loads the efficiency of most PSUs drops.

This... 80+ ratings are generally quoted for 50% PSU load.

[Spotty]

27 minutes ago, Hamster Homie said:

Hey, so I have a Corsair CX550M power supply. When I look at HWMonitor I see my CPU only pumping 12W at idle and my GPU 5W. I have a couple LED things such as an AIO, RAM and 1 fan but I don't think this sucks up much power. What I don't know is how much my motherboard and my cooling devices are taking. Now, looking at the efficiency curve of my PSU ( http://members.cybenetics.report:5050/d/cybenetics_CUj_eu.pdf )

The report you linked to is for the Corsair CX550. Different power supply than the CX550M.

This is the report for the CX550M. http://members.cybenetics.report:5050/d/cybenetics_xR6.pdf

 

It's normal for PSUs to have low efficiency at very low loads.

With your CPU, GPU, LEDs, drives, fans, etc... Let's say for simplicity sake you're idling at around 40W for the total system. With your CX550M you'd be drawing around 52W from the wall, which is approximately 75% efficient (as shown in the low load tests in the above cybenetics report). 75% efficiency is probably pretty normal for an 80+ Bronze rated PSU and might seem low when you hear "only 75%", but because you're drawing such a tiny amount of power to begin with it's only 12W that is being wasted. To put it in perspective at 275W (50% load) it would be around 88% efficient, which sounds much better, but that would mean it's drawing 312W with 37W being wasted - more than 3 times the energy wasted at low loads.

 

There are new requirements for better efficiency at low loads. The requirement is for 70% efficiency measured at 10W load for <500W PSUs or measured at 2% load for >500W PSUs. If you're really concerned about efficiency at low loads then you could look at replacing the PSU with one of those such as the new Corsair RM series, which taken as an example would be around 85% efficient at the same 40W load pulling 47W which is 5W less than the CX550M [Source: Cybenetics]. Because the difference in terms of power draw due to efficiency at low loads is so small it really wouldn't make any appreciable difference, not something you would notice on your power bill that's for sure.

 

10 minutes ago, Eighjan said:

This... 80+ ratings are generally quoted for 50% PSU load.

80+ ratings are based on meeting efficiency requirements at 20%, 50%, and 100%, with additional requirements at 10% load for 80+ Titanium.

[WihGlah]

It's a low efficiency of a really low number. The wasted energy at 100W is less than 15W.