Guide Downgrade PSU to Save Electricity Power?

CasualGamer91

CasualGamer91

Forerunner
Hello, I am looking to downgrade my PSU to save on electricity power consumption. But first here's my system specs below,

CPU: Ryzen 5 5600, (-30 CO undervolt @ 4.2mhz) (Max wattage 50-60watts)
GPU: Zotac Dual Fan Rtx 3060 12GB (0.812mv undervolt @1702mhz, max load = 105watts)
Motherboard: MSI b550m-a pro motherboard
Memory: 32GB 2x16GB Gskill Ram @ 3200mhz
Storage: WD black sn770 NVMe gen 4 ssd, crucial bx500 sata ssd, wd blue hdd 7200rpm

Total system power consumption is 190-220 watts measured from smart wall plug. Including inefficiency at below 20% PSU load. My current PSU is Silverstone DA850 80 Plus gold full moduler which is a 850 watt PSU and efficiency curve starting from 20% load at 87% to 90% at full load.

Problem is I don't use even the 20% of this gpu of my 90% pc time which I do work. 20% of 850 watts is 170 watts. So I'm thinking to downgrade to a PSU which also doesn't cost a lot of money and good enough for running the system efficiently.

From the wolfgang youtube channel I found the coolermaster mwe bronze 450 watt V2 is a good efficient PSU at lower wattage. This guy make homelab videos so he knows what he is doing for power efficiency. But I'm confused if it is worth it or not for a gaming pc which is intended to use normally most of the time. What do you guys think about the downgrade?
 
Heisen said:
I say not worth it. There are other things in house which must be playing a bigger role in your power bill than your PSU.
Click to expand...
My house is electricity is fairly optimised, led lights and DC motor fans of 40 watts. Problem is I want to keep the pc on at all times so idle power consumption adding with inefficiency and goes between 50-60 watts... Which should be 30-40 watts according to my calculations.
 
It won't make any real difference to your electricity bill for you to bother with all that hassle. Let me give you one personal example:

I run a 3080 with a 750W unit. I have my card maxed out, even the power limit. During peak usage (at least a few hours every day, even more during weekends), my GPU alone pulls more than 350W. PC is never off, except for a few hours every night.

I have gone through a month (each in both summer and winter) with my PC seeing zero usage. During that time, I only had a savings of less than 200 rs in my electricity bill, with all other use-case factors around the house staying similar.

Unless you want to save 100-200 every month (less than 2400/year), don't bother, and stay with a PSU that will see you through a future upgrade.

Of course, your own state's electricity costs will vary, so you'll be the best judge. Mine is based on Kolkata's figures.
 
Last edited:
PunkX 75 said:
It won't make any real difference to your electricity bill for you to bother with all that hassle. Let me give you one personal example:

I run a 3080 with a 750W unit. I have my card maxed out, even the power limit. During peak usage (at least a few hours every day, even more during weekends), my GPU alone pulls more than 350W alone. PC is never off, except for a few hours every night.

I have gone through a month (each in both summer and winter) with my PC seeing zero usage. During that time, I only had a savings of less than 200 rs in my electricity bill, with all use-case factors around the house, staying similar.

Unless you want to save 100-200 every month (less than 1500/year), don't bother, and stay with a PSU that will see you through a future upgrade.

Of course, your own state's electricity costs will vary, so you'll be the best judge. Mine is based on Kolkata's figures.
Click to expand...
Unit price 8rs here... Also im not upgrading for atleast next 5-8 years..
 
CasualGamer91 said:
My house is electricity is fairly optimised, led lights and DC motor fans of 40 watts. Problem is I want to keep the pc on at all times so idle power consumption adding with inefficiency and goes between 50-60 watts... Which should be 30-40 watts according to my calculations.
Click to expand...
Lets do some roi calculations, if you assume your average power consumption at PSU output is 60w, assume current psu efficiency is 80% and a mwe 450v2 efficiency is 85% at 60 watts, power difference at input is 60/0.8 - 60/0.85 ~ 4.5w.

4.5w would amount to 108Whr a day, ~40KWhr a year, which at 8rs is 320rs. Even if you keep the psu for 8 years, you won't make the roi.
 
  • Like
Reactions: gourav, YeAhx, Heisen and 2 others
StygianClaw said:
Be honest. You have an itch to buy new stuff and need a justification to do so :p
Click to expand...
Lol, I can relate, even if it's a downgrade. When the 750 Ti launched in 2014, because it was the first Maxwell card with crazy power efficiency vs performance, I wanted one. I was rocking an HD 7950 at the time, I sold that to buy the 750 Ti, which was a HUGE performance downgrade.
 
  • Like
Reactions: StygianClaw
StygianClaw said:
Be honest. You have an itch to buy new stuff and need a justification to do so :p
Click to expand...
Bro hahaha i dont know maybe yeah!

it is very rewarding and efficiency is nice to have.
PunkX 75 said:
Lol, I can relate, even if it's a downgrade. When the 750 Ti launched in 2014, because it was the first Maxwell card with crazy power efficiency vs performance, I wanted one. I was rocking an HD 7950 at the time, I sold that to buy the 750 Ti, which was a HUGE performance downgrade.
Click to expand...
Yeah bro its pointless to get more performance in expense of power. Always nice to have something that is can deliver good performance per watts also doesn't cost a lot of money.
 
I don't think downgrading to smaller psu will reduce power consumption.

PSU only supplies power to the components' demand. Rather, it could be that at 50% load or lesser the PSU has the best efficiency switching AC to DC.
 
  • Like
Reactions: sato1986
msvsme said:
I don't think downgrading to smaller psu will reduce power consumption.

PSU only supplies power to the components' demand. Rather, it could be that at 50% load or lesser the PSU has the best efficiency switching AC to DC.
Click to expand...
I heard psu efficiency is really bad when the usage is under 20% of the max capacity..
 
CasualGamer91 said:
I heard psu efficiency is really bad when the usage is under 20% of the max capacity..
Click to expand...
Doesn't mean it will consume high amount of electricity though. Efficiency decreases because there is (probably, as Im not an expert in this field) a minimum fixed amount of power draw from the outlet to PSU to keep it running so as you reduce the power usage that won't change that thus you get lower % efficiency. Sweet spot for PSUs will always be around 50-60% but the difference here is so minor that you are reaching "overthinking" category.

Also I looked at both the PSUs and the difference in percentage is about 3-5% roughly for your use case.
 
  • Like
Reactions: CasualGamer91
YeAhx said:
Doesn't mean it will consume high amount of electricity though. Efficiency decreases because there is (probably, as Im not an expert in this field) a minimum fixed amount of power draw from the outlet to PSU to keep it running so as you reduce the power usage that won't change that thus you get lower % efficiency. Sweet spot for PSUs will always be around 50-60% but the difference here is so minor that you are reaching "overthinking" category.

Also I looked at both the PSUs and the difference in percentage is about 3-5% roughly for your use case.
Click to expand...
5% of 850watts is 42.5watts. 5% of 450 watts is 22.5 watts
 
CasualGamer91 said:
5% of 850watts is 42.5watts. 5% of 450 watts is 22.5 watts
Click to expand...
That's not how it will be calculated for it. It's kinda hard for me to put into words but efficiency curves are showing efficiency loss at a given power usage in the graph curve so you will also calculate that loss at the same power usage of your PC (e.g. at 190-220W) and not at the max rated of the said PSUs.
So if we assume 5% of efficiency difference between both PSUs for your use case it will come out at about 11W difference (5% of 220W=11W).

TLDR: You will be saving 11 watts of electricity at most if you switched from your current 850W PSU to 450W. That comes at like what 3.7 days of continuous load to make 1 electricity unit difference? lol
 
  • Like
Reactions: sato1986
YeAhx said:
That's not how it will be calculated for it. It's kinda hard for me to put into words but efficiency curves are showing efficiency loss at a given power usage in the graph curve so you will also calculate that loss at the same power usage of your PC (e.g. at 190-220W) and not at the max rated of the said PSUs.
So if we assume 5% of efficiency difference between both PSUs for your use case it will come out at about 11W difference (5% of 220W=11W).

TLDR: You will be saving 11 watts of electricity at most if you switched from your current 850W PSU to 450W. That comes at like what 3.7 days of continuous load to make 1 electricity unit difference? lol
Click to expand...
You're right... Not worth it i guess. 60-70rs i will save monthly if pc never shuts down.. i spent that in chai sutta in a day
 
Top Bottom