Is there a place i can get low load PSU efficiency numbers

[EvilKitty]

Is there a efficiency chart/table for power supplies that includes 10% loads?

 

Reasons:

• I had a ~10 year old 300W bronze PSU go bad on me
• every retail PSU that is of quality is at least 450W, most are 550-650
• the 80+ labels do not apply to under 20% loads (barring titanium)
  • titanium units start at 750W at so i have the same issue as the rest of the labels

 

Seeing as how i only really need a 250W unit where the 20% load number would be relevant but with there are a whopping 0 reputable US retail PSUs i can spend money on for a low wattage build the only option is to buy around 2x the wattage i need or more at which point the 80+ badge is no longer relevant unless the system is under a 100% full synthetic load (CPU, network, HDDs, and SSDs) i am never gonna hit a 20% load on the PSU and for all i know i would be getting 40% efficiency 99% of the time.

 

Ok technically i was able to find a be quite 350W unit for sale and it is listed at over double what you can get a unit with a better warranty with double the wattage for

[Spotty]

Cybenetics does 10%-110% efficiency testing at 10% load increments as well as low load (20W-80W) efficiency testing at 20W intervals.

https://www.cybenetics.com/index.php?option=power-supplies

[EvilKitty]

just found out i can get 10% efficiency from the 80+ test results, they test 10% loads but as far i can tell from wikipedia 10% does not apply to the sticker requirements

 

https://www.clearesult.com/80plus/manufacturers/115V-Internal

 

upon sorting teh data that asus tuf 550w looks amazing

*reads report pdf*

oh that 10% load is a typo in the table...

[Alex Atkin UK]

Remember to consider that 10% difference in efficiency might only be a few watts depending on how low the load is.  So it could take years before the difference in price between a good and bad low-load PSU covers the difference in energy cost.

[EvilKitty]

the main thing i needed to check was to be sure it does not fall off a cliff at below 20% cause 20% it near max system power usage, since it will be running 24/7 i want to have a quality unit with a long warranty

 

i have ordered this unit: https://www.evga.com/products/product.aspx?pn=220-GA-0550-X1

i even found a coupon and got 6% off on top of the 'sale' price, much better than spending over 100$ on something similar even if that is 1% less efficient i will not even come close to the cost difference in power over 10 years and i do not expect any PSU to last long enough for the power savings to matter compared to the sale price

 

given i am expecting to never even pull 100W and buying a PSU rated at 550W is ridiculous for that, so the only number that matters is the 10% usage, unless i make/design my own PSU i do not see a reasonable way to get a low wattage quality unit (really do not have time for that, i would be better off recapping the old 300W unit)

[Spotty]

4 hours ago, EvilKitty said:

given i am expecting to never even pull 100W and buying a PSU rated at 550W is ridiculous for that, so the only number that matters is the 10% usage, unless i make/design my own PSU i do not see a reasonable way to get a low wattage quality unit (really do not have time for that, i would be better off recapping the old 300W unit)

There's not much cost difference between making a good & efficient 200-300W unit compared to a 450-550W unit. There is a base cost when making a PSU and going down in wattage won't reduce that after a point. The assembly cost is going to cost the same, designing and manufacturing the PCB, a 120mm-140mm fan, all the testing and certifications... You might be able to drop some cables, cheaper rectifiers, smaller bulk capacitor, smaller heatsinks... All up saving a few dollars at best. If people have the choice between a 300W power supply for $50 and a 550W power supply for $55 everyone is going to pick the 550W one.

Power supplies are already pretty efficient above 10% load. There are new standards for higher efficiency at extremely low loads. The new ATX 3.0 standard is requiring 60% efficiency (and is recommending 70% efficiency) at 2%/10W load.

 

The other option for <200W load could be a pico PSU which uses a laptop style adapter and then the Pico PSU is just stepping down DC to DC to generate the 12V/5V/3.3V/5VSB/-12V. The DC-DC step down conversion is typically very efficient, but you're still going to have some efficiency losses from the AC/DC power adapter similar to a normal power supply so they normally won't be any more efficient than a regular power supply. Pico PSUs are more for their compact size, not efficiency. You're also often limited on power connectors with just the bare minimum with Motherboard 24pin, CPU, and maybe one or two SATA power connectors.

 

4 hours ago, EvilKitty said:

the main thing i needed to check was to be sure it does not fall off a cliff at below 20% cause 20% it near max system power usage, since it will be running 24/7 i want to have a quality unit with a long warranty

 

i have ordered this unit: https://www.evga.com/products/product.aspx?pn=220-GA-0550-X1

i even found a coupon and got 6% off on top of the 'sale' price, much better than spending over 100$ on something similar even if that is 1% less efficient i will not even come close to the cost difference in power over 10 years and i do not expect any PSU to last long enough for the power savings to matter compared to the sale price

The EVGA GA 550W should be good and under $60 is a decent price for a 550W 80+ Gold PSU

I'm sure you've already checked the 80+ report but it shows 85% efficiency at 10% load and just shy of 90% efficiency at 20% load. Unfortunately no Cybenetics report for the GA models yet so can't get more detailed efficiency results.

Edited August 22, 2022 by Spotty

[EvilKitty]

Cybenetics did review the 650W or was that the 750W variant of that unit, though it is not really a good idea to try to extrapolate another PSU from that series as they could have different OEMs

 

was looking at warranty duration and and 10% load data for the lowest wattage PSU in the product stack, real shame that ASUS tuf was not ~95% efficient (the PDF report shows they typed a 8 as a 9)