are power supply calculators good?

[ComputerPerson1867]

im using one to see if i can do an rx 570 with a ryzen 3 2200g cpu for 450 watt power supply and it says its fine. should I believe the psu calculator i found online or is it inaccurate? the psu calculator is outervision. If this is a bad one does anyone know any good ones out there?

[Spotty]

Power Supply calculators tend to be rubbish, and Outervision is one of the worst. It will overestimate in order to convince people to buy more expensive, higher wattage power supplies.

 

Outervision will recommend 100W when you don't have any hardware at all. No CPU, no GPU, no Motherboard... Nothing!

https://linustechtips.com/main/profile/519965-spotty/?status=250185&type=status

You're far better off looking at your individual components and looking at reviews which test how much power each component uses.

4 minutes ago, unevendaxter said:

im using one to see if i can do an rx 570 with a ryzen 3 2200g cpu for 450 watt power supply and it says its fine.

Your Ryzen 2200G + RX 570 system will be perfectly fine with a 450W power supply.

Ryzen 2200G (CPU only since you're using dedicated GPU) will require around 55W under heavy load. https://www.tomshardware.com/reviews/amd-raven-ridge-thermal-power-benchmarking,5464-5.html

RX 570 will require around 150W under load. https://www.tomshardware.com/reviews/amd-radeon-rx-570-4gb,5028-15.html

 

200W for your CPU & GPU. Add another 50W or so for things like motherboard, RAM, fans, SSD, HDD. Total power draw for the system will be around 250W.

[ComputerPerson1867]

6 minutes ago, Spotty said:

Power Supply calculators tend to be rubbish, and Outervision is one of the worst. It will overestimate in order to convince people to buy more expensive, higher wattage power supplies.

 

Outervision will recommend 100W when you don't have any hardware at all. No CPU, no GPU, no Motherboard... Nothing!

https://linustechtips.com/main/profile/519965-spotty/?status=250185&type=status

You're far better off looking at your individual components and looking at reviews which test how much power each component uses.

Your Ryzen 2200G + RX 570 system will be perfectly fine with a 450W power supply.

Ryzen 2200G (CPU only since you're using dedicated GPU) will require around 55W under heavy load. https://www.tomshardware.com/reviews/amd-raven-ridge-thermal-power-benchmarking,5464-5.html

RX 570 will require around 150W under load. https://www.tomshardware.com/reviews/amd-radeon-rx-570-4gb,5028-15.html

 

200W for your CPU & GPU. Add another 50W or so for things like motherboard, RAM, fans, SSD, HDD. Total power draw for the system will be around 250W.

thanks so much for the help

[Otto_iii]

just like tie a lead to your ankle, plug yourself into the grid, and laydown over your mobo, this is the most intense gaming experience you can get and at very little to no cost

honestly though i agree with what dogwolfman spotty said, most calculators presume you need more then you actually do, that said its usually best to over-purchase with PSU as it will outlast the rest of components assuming it isn't of poor quality and causes issues, for this reason, at the very least try to buy a 80+ Bronze type 450W, but if you can get a 550W 80+ Bronze, that will likely continue to work with any system configuration you can come up with now that SLI/Crossfire is dead and gone. 

[NineEyeRon]

PC Part Picker has one built in.

 

When I put my system in it says I can have any GPU, I know my CPU is pulling about 120W and the rest is just two SSDs,  a few fans and the USB ports (which I always assume to be fully used). Even with the 5600XT I still have 100+ watts to spare with a 550W PSU.

 

Unless you have fancy water cooling or a well OCed system then 550 will do most people. 750 will do almost everyone bar some edge cases.

[Mantabase]

20 hours ago, unevendaxter said:

thanks so much for the help

The above posters are likely right.  For me - If I guess ~250-275 watt for the GPU and CPU (please tell me if I am wrong) and build out a "typical" system for gaming. 

 

EDIT - I guess 250-275 is high - so know 50 watts off the below.

 

HHD: = RPM/350

SSD = 10 watts each

Optical = 30 watts

MB= 100-120 watt per CPU.

RAM = 0.5 watt/gig

 

1hdd (7500 RPM), 1 ssd, 1 optical, MB, 16g RAM = 22 + 10 + 30 + ~110 + 8 = 180 + 275 = 455.  Newegg calculator says 427.

 

I usually multiply by 1.2 for longevity, to keep in the "green zone" of the PSU, and make sure I have enough amps per rail -  so 546 ( or 550) is what I would go for. But I like overhead.  So 450 is probably fine, especially if you have no optical or HDD.  Newegg says 377 in that case (no idea how good Newegg calc is).

Edited December 21, 2019 by Mantabase
update wattage

[Mantabase]

22 hours ago, Spotty said:

Outervision is one of the worst.

It gave me about 400 watts.  It seems pretty close (at low watts) - but I understand they have incentive to bump the number up.  Interesting little post - uses 50 but buy 100.  The issue may be that you can't just add up all the max's on your hardware and get a truly good number.

 

I'm sure you know this (so maybe someone else will get something from  it), but if I add everything up based on tested loads and then use the spec for the motherboard I will end up with a system that doesn't have enough power because of efficiency problems (EDIT - that's misleading - I mean problems with how the rails are divided for the maker to get efficiency ratings - not that a say 450 won't put out 450).  Make matters worse, it will be running in the least efficient range (if it runs) of the PSU much of the time.  That means more cooling will be needed and the PSU will fail sooner.  Best to never exceed 80% total wattage or 90% of a given rail - and typically run between 40-60% on all (well....if possible- 3.3 is a little tough).  That means you should add overhead to stay in that green zone.  Maybe that is what it is.

Anyway, If I recommended a PSU to the OP it would be 550 and a reputable brand - so I think Outervision is actually low.  But they didn't ask for that - just if 450 would work - and like you say, it should be fine.  Plus - we don't know the specifics of the OP's build.

[Spotty]

23 minutes ago, Mantabase said:

I'm sure you know this (so maybe someone else will get something from  it), but if I add everything up based on tested loads and then use the spec for the motherboard I will end up with a system that doesn't have enough power because of efficiency problems.  Make matters worse, it will be running in the least efficient range (if it runs) of the PSU much of the time.  That means more cooling will be needed and the PSU will fail sooner.  Best to never exceed 80% total wattage or 90% of a given rail - and typically run between 40-60% on all (well....if possible- 3.3 is a little tough).  That means you should add overhead to stay in that green zone.  Maybe that is what it is.

None of that is true. There's no "efficient range" or "green zone" for a power supply that you need to target. You don't need to keep it between 40-60% for it to work or be efficient. It's not going to blow up if you exceed 80%. 

 

The "least efficient zone" is under 20% load. So buying a larger PSU than you need is more likely to make it less efficient. 

 

Here's an efficiency graph for a modern power supply (RM550x - 550w)

 

After you hit about 20% load it's pretty much a straight line that only gently falls off. Peaks at 92% efficiency between 200-400w, dropping to 91% efficiency at 550w. Only 1% difference. Doesn't make any real difference.

 

If you want a more efficient power supply, buy a power supply with a higher efficiency rating. Buy 80+ gold instead of 80+ bronze.

 

34 minutes ago, Mantabase said:

Interesting little post - uses 50 but buy 100. 

You missed the point. It's not that it's recommending 100w when it's using 50w. It's that a system without any hardware according to outervision uses 50w. Just 50w evaporating in to thin air. That value should have been 0w since there was no hardware.

[Mantabase]

58 minutes ago, Spotty said:

None of that is true. There's no "efficient range" or "green zone" for a power supply that you need to target. You don't need to keep it between 40-60% for it to work or be efficient. It's not going to blow up if you exceed 80%. 

 

The "least efficient zone" is under 20% load. So buying a larger PSU than you need is more likely to make it less efficient.

Well, let's be fair here - I never said it would "blow up" over 80%.   Try not to put words in my typing.  I agree buying a PSU that is too big is an issue.

 

The most efficient zone is generally 40-60% in a PSU - your plot shows that and other PSU have a more dramatic curve.  So, don't tell me it is not true - you just showed it (all respect intended).  Now to you, the difference between 91.5 and 87.5 means nothing.  But to the PSU that means that at plus 60 and certainly at over 80% you are out of the "sweet spot" (if the word "green" bothers you).  That means more heat in the CPU from both load and less efficiency which means more cooling.  Now - I realize that won't heat your room or case much with smaller systems (and is only maybe 3-6 watts of power) - but it does heat the components on the PSU, increase resistance and run the fan hard and louder generally lowering the life on an important part (the entire PSU) and making unneeded noise.

 

As far as missing the point - when you put non-sense into a computer, you might expect non-sense out.  I don't think a 400 or 450 watt recommendation to the OP is over the top.  Do you?  

 

EDIT - just to be clear - I am not trying to start a fight here - I just don't agree.  Maybe I'm too conservative with PSU's and thus over estimate.