[SOLVED] How inefficient is a high wattage PSU (eg 850W) versus a low wattage PSU at low loads?

[OZZERO]

Is there any meaningful difference in PSU inefficiency between 850W PSUs, and say 650W PSUs at low loads?

Would an 850W Platinum be better than a 650W Gold at low loads (eg 50-100w)?

 

[tennis2]

From a high level:
https://en.wikipedia.org/wiki/80_Plus
Modern platforms have a much flatter efficiency curve than ever.

But you're in the 5-15% tier. For that, you're probably looking at around 85-87% efficiency around the 10% load for a good/modern platform.

Some manufacturers will provide the efficiency curve.

JonnyGuru could provide much better details.

 

[Juular]

0.2-0.3% difference.

Spoiler

https://www.techpowerup.com/review/corsair-rm1000x/6.html

Spoiler

Corsair RM550x Power Supply Review

The lowest-capacity unit Corsair's RMx line outputs up to 550W and is 80 PLUS Gold-certified. It features fully modular cabling, offers great performance and is nearly silent throughout its operating range, too.

www.tomshardware.com

Why are you asking ?

 

[OZZERO]

0.2-0.3% difference.

Spoiler

https://www.techpowerup.com/review/corsair-rm1000x/6.html

Spoiler

Corsair RM550x Power Supply Review

The lowest-capacity unit Corsair's RMx line outputs up to 550W and is 80 PLUS Gold-certified. It features fully modular cabling, offers great performance and is nearly silent throughout its operating range, too.

www.tomshardware.com

Why are you asking ?

I found a good deal on a 850W Corsair and wondered if I should just go for that. I currently have a 650W Gold PSU but was looking to upgrade in preperation for the new GPUs. However, as most of my time on the computer is spent doing general office work, I didn't want to see more heat/wastage/increased bills - if that makes sense.

 

[tennis2]

Uhh, pretty sure there are ZERO good deals on PSUs in 2020.

 

[Ziadul87]

Uhh, pretty sure there are ZERO good deals on PSUs in 2020.

Yeah. And I'm pretty sure my whole country is out of Corsair PSU stocks right now. Only a 500$ AX1500i available online and for good reasons. XD

 

[Vic 40]

If he says he has a good deal i can only guess he has, why are you two being like "that".

I found a good deal on a 850W Corsair and wondered if I should just go for that. I currently have a 650W Gold PSU but was looking to upgrade in preperation for the new GPUs.

Don't think bills will become higher, think at those loads you ask about they are pretty similar and maybe even that the Platinum is abit more efficient. Which psu exactly might make a difference as well.

haven't looked yet, but maybe wait untill they really know what power the new gpu's use, than again that deal you seem to have might be gone then.

 

[Ziadul87]

If he says he has a good deal i can only guess he has, why are you two being like "that".

Nah. I'm just saying about the condition of PSU here in my region. There are still good deals hanging around. But not in my country and not Corsair.

 

[jonnyguru]

I found a good deal on a 850W Corsair and wondered if I should just go for that. I currently have a 650W Gold PSU but was looking to upgrade in preperation for the new GPUs. However, as most of my time on the computer is spent doing general office work, I didn't want to see more heat/wastage/increased bills - if that makes sense.

What Corsair 850W PSU?

Below 10% load, PSU efficiency pretty much TANKS.

Unless the PSU uses an LLC controller that switches to burst mode at low loads. Currently, the only Corsair PSU that does that is the RM (non-x, non-i).

 

[OZZERO]

https://www.scan.co.uk/products/850...d-sli-crossfire-single-rail-708a-135mm-fan-at

@tennis2 @Ziadul87 Here is the good deal I found. Seems like a very reasonable price for a PSU.

What Corsair 850W PSU?

Below 10% load, PSU efficiency pretty much TANKS.

Unless the PSU uses an LLC controller that switches to burst mode at low loads. Currently, the only Corsair PSU that does that is the RM (non-x, non-i).

RM 850x

Is that true for all PSUs regardless of efficiency rating (eg Platinum)?

 

[Ziadul87]

https://www.scan.co.uk/products/850w-corsair-rmx-series-rm850x-full-modular-80-plus-gold-sli-crossfire-single-rail-708a-135mm-fan-at

@tennis2 @Ziadul87 Here is the good deal I found. Seems like a very reasonable price for a PSU.


RM 850x

Is that true for all PSUs regardless of efficiency rating (eg Platinum)?

Nice deal indeed. ~80% of the price mentioned in corsair's website.

 

[tennis2]

£110?
https://uk.pcpartpicker.com/product...-fully-modular-atx-power-supply-cp-9020180-na

RMx is their 2018 model and RM is their 2019 model? I really hate Corsairs naming, cuz I'm pretty sure they had RM before RMx also....

 

[Vic 40]

Below 10% load, PSU efficiency pretty much TANKS.

What do you call "Tanks"? To bronze level or really worse? He was talking about between 50<->100watts usage.

 

[jonnyguru]

What do you call "Tanks"? To bronze level or really worse? He was talking about between 50<->100watts usage.

< 60% is not uncommon.

You have to switch to burst mode just to get 70%+.

 

[Vic 40]

But that is with any psu? Yeah i know Under 10% it wil tank. Problem seems to be RTX 3000 which they say will use alot. So a higher wattage psu needed.

@OZZERO,

what is the purpose of the psu? For what parts?

 

[Juular]

What do you call "Tanks"?

This :

But thing is, most modern PSUs, Gold or Platinum rated would behave the same and even if there would be like 10% difference between the two at low load, with ~50W total power draw that's just about 5W which you wouldn't see in your bills at all.

 

[Vic 40]

Yeah nice graph, but in that one is below 60% already at near 25watts not the 50<->100watt the op asks about. Looks more like 80/82% at those loads.

 

[jonnyguru]

Yeah nice graph, but in that one is below 60% already at near 25watts not the 50<->100watt the op asks about. Looks more like 80/82% at those loads.

Well... that's because it's an excellent PSU, of course. 😀

 

[Vic 40]

Well... that's because it's an excellent PSU, of course. 😀

OP is looking at RMx 850 watt 😉

https://www.scan.co.uk/products/850...d-sli-crossfire-single-rail-708a-135mm-fan-at

@tennis2 @Ziadul87 Here is the good deal I found. Seems like a very reasonable price for a PSU.


RM 850x

Is that true for all PSUs regardless of efficiency rating (eg Platinum)?

 

[jonnyguru]

OP is looking at RMx 850 watt 😉

Yeah. Low load efficiency could be better, though. Next years' version will have that "fixed" by replacing the current LLC controller with one with burst mode < 10% load.

 

[OZZERO]

This :

But thing is, most modern PSUs, Gold or Platinum rated would behave the same and even if there would be like 10% difference between the two at low load, with ~50W total power draw that's just about 5W which you wouldn't see in your bills at all.

True. I guess I'm just overthinking this all haha. Will probably stick to the RMx instead of the HX series in that case.

 

[tennis2]

To be fair, RTX 3080 reviews are out, so we know exactly how much power that card uses. Go lower on the stack, and power draw will decrease obviously.

At low loads, one could ask: Why does it matter? Even if 60% efficiency,, that's 100W system power draw = 166W from the wall. If your PC is sitting completely idle for that long of a duration that the extra 0.066KWHr matters on your utility bill, maybe turn it off.....