Power Supply Desktop PC

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kiwis

832 posts

Ultimate Geek

#282664 4-Mar-2021 21:25

When I upgraded my PC last year I used an old 500W PSU.

At the time I was told to get a 650+ and see many gaming rigs with feedback to get a 700 or 750W PSU.

Two questions

1) What does the higher PSU give you? Is there a performance boost or what’s the reason?

2) If I was upgrade - what am I looking for? Specs below. Current PSU is all plug and play. Easy to install from unit to components

B450 Pro Board
3600X CPU
RTX 2060 Super GPU
16GB RAM (may go to 32GB)
2x 1TB SSD
2x 3TB HDD
Fan cooling

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#2667967 4-Mar-2021 22:48

Higher PSU just ensures all your gear is getting what it needs to run. If you tried running all that on a 250W PSU, you'd hit issues pretty quick :D

You'd probably be OK with a 500W, but for a few $$ extra look at 600+ to ensure coverage.

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fe31nz

1228 posts

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#2667995 5-Mar-2021 00:25

It is much better to work out you actual power need and use a power supply of the right size. Power supplies only work at their rated efficiency over a limited range. If you put a 2000 W power supply on a system that is normally only using less than 200 W, it will be working below 10% of its capacity and will be badly inefficient, increasing your power bill and heating the room it lives in. Check the specifications of any power supply you intend to use and make sure your normal use will fall in the range where it works most efficiently (typically 20%-80% or 15%-85%).

Also, when buying power supplies, it does pay not to buy the cheapest one - they normally do not last long and are badly inefficient. It is preferable to pay rather more and get an 80+ rated one from a reputable manufacturer which will last and will pay for its extra cost in lower power bills over its lifetime.

timmmay

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#2668001 5-Mar-2021 06:28

I put an approximation of your parts into PC parts picker link and it says your components use a peak of 379W. That's when CPU and graphics card are at 100%, if you measure it (I have measured my computers) it will probably be using about 100W most of the time. Power supplies aren't 100% efficient, so adding 25% to 379W says 473W PSU would handle the load easily, so 500W is perfect. Going larger has few advantages - maybe large supplies have better cooling - but PC performance will be identical unless the PSU can't supply the power required.

Dial111

978 posts

Ultimate Geek

#2668003 5-Mar-2021 06:40

fe31nz: If you put a 2000 W power supply on a system that is normally only using less than 200 W, it will be working below 10% of its capacity and will be badly inefficient, increasing your power bill and heating the room it lives in.

Your computer will only draw what it needs from the psu not the other way around, it's totally fine to use higher rated psu's there is no wasted power draw

Dial111

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#2668006 5-Mar-2021 07:09

Only wasted money

timmmay

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#2668007 5-Mar-2021 07:28

Dial111: Only wasted money

Not on power, just on the power supply. Larger power supplies don't cost all that much more than smaller ones, but yes they are a bit more expensive.

1101

3122 posts

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#2668022 5-Mar-2021 08:50

RTX 2060
Minimum recommended is 500 W
Go from there

I would say better quality is more important than slightly higher power.

but
Even the el -cheapo dont fail as common as some would have us believe.
There are many thousands of PCs out there still happily running with the nastiest cheap power supplies .

get a PSU that goes to 11 :)
https://www.youtube.com/watch?v=hW008FcKr3Q

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timmmay

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#2668083 5-Mar-2021 09:19

My Cooler Master 500W purchased recently was faulty. The computer booted, it caused some really weird problems until PB diagnosed and replaced.

kiwis

832 posts

Ultimate Geek

#2668101 5-Mar-2021 10:01

So the online calculators say I need around 400W but the specs for my GPU say minimum of 550W power?!

Would the GPU under perform with lower power? Or preform better with higher power than what I have?

richms

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#2668156 5-Mar-2021 11:08

Those ratings are generally given taking into account that most people who need to go by them are cheap and buying the cheapest PSU they can find that meets that rating and those will be lies on it. Friends machine should have a 750 according to calculators. Never goes over 280 from the wall when gaming and not much more than that running the tests.

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Jase2985

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#2668181 5-Mar-2021 11:58

Have you had any issues with random shutdowns or crashes?

if not your current PSU is likely fine watts wise so no reason to worry.

timmmay

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#2668192 5-Mar-2021 12:16

kiwis: So the online calculators say I need around 400W but the specs for my GPU say minimum of 550W power?!

Would the GPU under perform with lower power? Or preform better with higher power than what I have?

Not really sure what happens if your PSU can't supply the power needed. Maybe the PSU will try and will overload / overheat / fail. Maybe weird things will happen in the system.

But most people and places overstate the power required to run hardware.

Dial111

978 posts

Ultimate Geek

#2668285 5-Mar-2021 15:01

timmmay:
kiwis: So the online calculators say I need around 400W but the specs for my GPU say minimum of 550W power?!

Would the GPU under perform with lower power? Or preform better with higher power than what I have?

Not really sure what happens if your PSU can't supply the power needed. Maybe the PSU will try and will overload / overheat / fail. Maybe weird things will happen in the system.

But most people and places overstate the power required to run hardware.

the PSU will shut down when its overloaded that's pretty much it, works the same as how a fuse would trip to break the current

ratsun81

508 posts

Ultimate Geek

#2668362 5-Mar-2021 16:36

kiwis: So the online calculators say I need around 400W but the specs for my GPU say minimum of 550W power?!

Would the GPU under perform with lower power? Or preform better with higher power than what I have?

No your GPU will not underperform it will either work or it wont.

The reason that a minimum is stated is because of other variables that are possible for the computer.

TL;DR

Voltage rails on a PC PSU are setup to handle a max value for a number of devices.
HDD's

EPS
CPU
GPU

If you push too much through these rails there is some limited balancing, after that you start causing operating issues.

PSU and GPU specs say that X+X+X=y is safe.... so run with that.

There are cheap PSU's so the above attempts to hold true for those.

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shrub

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#2668363 5-Mar-2021 16:40

The main reason for having more than recommended is for spike loading on CPU/GPU. These parts can draw a lot initially then reduce power consumption when heat rises. Also they don't know that your running a 65w CPU you could have a 135w CPU.

Peak is normally after 10min of 100% load once the system temperatures stabilizes. Ryzen 3600x will load up to 4.3 then drop to 4.0 during this time it can draw 60-100w. RTX2060 will draw roughly 200w CPU + mobo + ram 150w at peak.

In some games 80% of the time the CPU is Idle-20% usage but it will encounter large spikes when say loading a map. The GPU will generally be pegged at 100% 200w the entire time which is why GPU manufactures recommend a slightly over sized supply 550w in your case.

If your not running an insane number of spinning rust or RGB then the 500w will be fine.

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