PSU - Corsair 750W ATX 3.1 vs 850W ATX 3.0

[David]

Still struggling with PSUs.

Amazon has this:
<https://www.amazon.co.uk/Corsair-RM750e-Modular-Low-Noise-Supply/dp/
B0BYKT9SNJ/?th=1>
which is actually the 850e at £88.99.

There is also:
<https://www.amazon.co.uk/Corsair-RM750e-Modular-Low-Noise-Supply/dp/
B0BYKHQWXF/?th=1>
at £84.99 (allegedly down from £129.90).

I would normally go for the more powerful option, but the 750e is on a big
discount compared to other suppliers whilst the 850e is only a few pounds
cheaper.

I deduce that the difference must be ATX 3.0 vs ATX 3.1.

The use is for my venerable desktops (as I thing two of them have dodgy
PSUs).
However I suppose I should have one eye on the future in case I have to
replace the MoBo.

Is ATX 3.1 relevant to anything apart from the latest high powered
machines?

As usual, I am swamped by too many options!

Help!


Dave R

[Theo]

Post by David
Still struggling with PSUs.
<https://www.amazon.co.uk/Corsair-RM750e-Modular-Low-Noise-Supply/dp/
B0BYKT9SNJ/?th=1>
which is actually the 850e at £88.99.
<https://www.amazon.co.uk/Corsair-RM750e-Modular-Low-Noise-Supply/dp/
B0BYKHQWXF/?th=1>
at £84.99 (allegedly down from £129.90).
I would normally go for the more powerful option, but the 750e is on a big
discount compared to other suppliers whilst the 850e is only a few pounds
cheaper.
I deduce that the difference must be ATX 3.0 vs ATX 3.1.
The use is for my venerable desktops (as I thing two of them have dodgy
PSUs).
However I suppose I should have one eye on the future in case I have to
replace the MoBo.
Is ATX 3.1 relevant to anything apart from the latest high powered
machines?
As usual, I am swamped by too many options!

https://www.corsair.com/uk/en/explorer/diy-builder/power-supply-units/atx-30-vs-atx-31-whats-the-difference/

It seems to be the only main difference is to do with high power GPUs, which
were/are a mess due to the new 12VHPWR connector catching fire in certain
circumstances.

Efficiency reports for the RM750e:
https://www.clearesult.com/80plus/sites/80plus/files/manufacturer-certificate/CORSAIR_RPS0147%20%28CP-9020248%29%20%28RM750e%29_750W_SOCE%206548_Report.pdf

and RM850e:
https://www.clearesult.com/80plus/sites/80plus/files/manufacturer-certificate/CORSAIR_RPS0157%28CP-9020249%29%28RM850E%29%20_850W_SOCE%206787_Report.pdf

shows there's not a lot in it efficiency wise (bear in mind though that
these are measured at % of full load, so for a fixed load you'll take a
higher percentage of max load on the smaller PSU. Really what you want is
to draw a horizontal line on the red line plot at a fixed power and measure
the thickness of the red line there - but here it looks pretty similar)

Unless you think you're going to be fitting a jumbo GPU in future, either
should be fine for a domestic PC, whose power will often barely touch 100W
most of the time.

Theo

[David]

Post by Theo

Post by David
Still struggling with PSUs.
<https://www.amazon.co.uk/Corsair-RM750e-Modular-Low-Noise-Supply/dp/
B0BYKT9SNJ/?th=1>
which is actually the 850e at £88.99.
<https://www.amazon.co.uk/Corsair-RM750e-Modular-Low-Noise-Supply/dp/
B0BYKHQWXF/?th=1>
at £84.99 (allegedly down from £129.90).
I would normally go for the more powerful option, but the 750e is on a
big discount compared to other suppliers whilst the 850e is only a few
pounds cheaper.
I deduce that the difference must be ATX 3.0 vs ATX 3.1.
The use is for my venerable desktops (as I thing two of them have dodgy
PSUs).
However I suppose I should have one eye on the future in case I have to
replace the MoBo.
Is ATX 3.1 relevant to anything apart from the latest high powered
machines?
As usual, I am swamped by too many options!

https://www.corsair.com/uk/en/explorer/diy-builder/power-supply-units/

atx-30-vs-atx-31-whats-the-difference/

Post by Theo
It seems to be the only main difference is to do with high power GPUs,
which were/are a mess due to the new 12VHPWR connector catching fire in
certain circumstances.
https://www.clearesult.com/80plus/sites/80plus/files/manufacturer-

certificate/CORSAIR_RPS0147%20%28CP-9020248%29%20%28RM750e%29_750W_SOCE%
206548_Report.pdf

Post by Theo
https://www.clearesult.com/80plus/sites/80plus/files/manufacturer-

certificate/CORSAIR_RPS0157%28CP-9020249%29%28RM850E%29%20_850W_SOCE%
206787_Report.pdf

Post by Theo
shows there's not a lot in it efficiency wise (bear in mind though that
these are measured at % of full load, so for a fixed load you'll take a
higher percentage of max load on the smaller PSU. Really what you want
is to draw a horizontal line on the red line plot at a fixed power and
measure the thickness of the red line there - but here it looks pretty
similar)
Unless you think you're going to be fitting a jumbo GPU in future,
either should be fine for a domestic PC, whose power will often barely
touch 100W most of the time.
Theo

Thanks.

The reports I have read thus far seem to say that both use the same set of
components, although they differ on how good/bad this is.
Mainly reviewers seem to like Japanese components more.

Based on all this I can't really see a justification for the much higher
list price (or at least the general non-discounted price) of the 750W
unless it is purely on the GPU power lead and slightly more recent
certification.

I think I will go for the 850W for the extra bit of headroom.
As usual, I probably won't know if I have made the correct decision for
months, if not years.

Cheers



Dave R