Power Supply Requirements

[temps]

I am wanting to build a PC with the following specs:

Ryzen 5600X
Some ATX motherboard
Either RTX 3070 or Radeon 6800
1-2 tb SSD
32 gb RAM
Big Noctua air cooler, lots of case fans (seems probably overkill for this CPU, but I kinda want to add these anyway)
*I also want to be able to overclock in the future, and the PSU calculator presumably doesn't account for that.

When I put this into Newegg's PSU calculator (minus the fans, b/c it doesn't let you put that info in), it's telling me I need a PSU of approximately 510 watts.

I threw an RTX 3080 into the calculator even though it's a step-up from what I really wanted to use, as well as another 2 SSD (because I was assuming I may want to add hard-drive storage at some point in the future, and upgrade to a graphics card that might be more power-hungry.

And yeah, it's saying I need about 510 watts. That seems pretty low to me because the last two PCs I built using guidance from others had PSUs of 650w to 800w... and I remember when I was on one of those previous two PCs that I had wanted to upgrade my GPU at some point and couldn't use the card I wanted because I didn't have the power in my PSU.

So doesn't it seem like I should be getting PSU with a lot more watts than that? Seems hard to know really because I don't know what the power requirements of FUTURE graphics cards will be 3 years down the road. And based on that, shouldn't I err on the side of caution and get more watts?

What do you guys think?

[Illusion of Progress]

Sounds about right to me. People vastly overestimate what wattage the typical PC needs. While newer GPUs are supposedly pushing it upa bit, the modest quad core and mid-to-high tier GPU combination would be fine on 450W to 550W. Everything THINKS a PC NEEDS 650W to 750W+ but this is far from true. If you're not going for a very top tier GPU and a very top tier and/or very high core count CPU, it cuts back drastically on what you'll need.

That being said, a 750W PSU would probably be what I'd look for. As far as I know, the middle range wattage (450 W to 650 W) are more scarce and expensive, but maybe that's changed in recent months. A 650W PSU would be fine for a Ryzen 5 5600 and RTX 3070 (though if you're potentially considering a 3080, I'd step up to 750W though). 850W+ is pretty much overkill but if you find it for the same price, I don't see why not.

[_I_]

psu calcs are overrated
so so are amd/nvidia min requirements for their gpus
(both are assuming poor quality overrated psu, gpu mfg with high tdp cpu and lots of accessories)

min req = cpu tdp + gpu tdp + 100 (mobo/ram/basic usb hardware) + 100w (overhead)
add 10w for each extra drive or fan


5600x = 65w (no way its really this low assume 80w)
https://www.anandtech.com/show/16214/amd-zen-3-ryzen-deep-dive-review-5950x-5900x-5800x-and-5700x-tested/8

3070 = 220w
rx 6800 = 250w

80+250+200 = 530w minimum with a quality psu that can actually output that safely

but psus are rated by input wattage not output, most are 80-90% efficient so tack on 20% or subtract it from the 100w overhead

recommended should be around 660w (530/80%)
pick up a seasinc, corsair (non v series), evga, or bequiet

[Nabster]

You need 650w for 3070 and 750w for 3080, just as an extra 100w if you want some headroom

[temps]

And if I get a PSU with an excessively high wattage, that won't hurt my PC build at all right? It would just be an inefficient use of $$ to build the PC?

[Autumn_]

引用自 temps：

And if I get a PSU with an excessively high wattage, that won't hurt my PC build at all right? It would just be an inefficient use of $$ to build the PC?

No, extra wattage won't harm your PC in any way.

But, by spending more, you could infact be saving (though, the extra money on the PSU will probably be about as much as you save) on your power bill, depending on the model.
If you get a model that is ~double what you need, you can reach peak efficiency.
Meaning less power is converted to heat, so you don't need to draw as much, saving power.
Though, like I said, depends on the model, some PSUs have an efficiency curve that is a straight line, so it is the same efficiency throughout the range of delivery.

If you buy a larger one, it should allow you to have any upgrade you would want in the future, and as the parts age, cause it to last longer.

So, a bigger PSU isn't a bad thing, but it's going to cost more.

[_I_]

most psus are more efficient at 50-80% load range
too high is not bad, but way too high, 500w+ over can reduce its efficiency further

[temps]

I was just reading through the specs of different GPUs, and when I look at the specs of these graphics cards, some like the XFX 6800 XT says it requires a 750 watt PSU minimum, and that XFX recommends an 850w power supply.

https://www.newegg.com/xfx-radeon-rx-6800-xt-rx-68xtacbd9/p/N82E16814150844

And the RTX 3080s I looked at recommend a 750 watt PSU as well.

So now I'm wondering why the PSU recommendations of the PSU calculator are differing so much from what the GPU spec sheet says is required...

[Autumn_]

引用自 temps：

I was just reading through the specs of different GPUs, and when I look at the specs of these graphics cards, some like the XFX 6800 XT says it requires a 750 watt PSU minimum, and that XFX recommends an 850w power supply.

https://www.newegg.com/xfx-radeon-rx-6800-xt-rx-68xtacbd9/p/N82E16814150844

And the RTX 3080s I looked at recommend a 750 watt PSU as well.

So now I'm wondering why the PSU recommendations of the PSU calculator are differing so much from what the GPU spec sheet says is required...

Current isn't drawn constantly, you have current spikes (depending on load), so you want to give some headroom for those.
Whenever you see TDP, or people checking powerdraw of hardware, it's averaged.

Vega liked to draw lots of current, so a PSU that would've been fine for it's average, may not have handled its spike very well, and would shut down.

That's one of the reasons why they recommend higher wattage. And, to make sure that if people do follow this recommendation, they don't run into issues, and think their GPU is garbage.
Aswell as everything else you may be running on the PSU - CPU, Motherboard, RAM, fans, drives, RGB, etc. It's better for them to recommend something that would just work, than to recommend something that could potentially not work on a few select systems.
So they always recommend higher than what you would need.

PSU calculators calculate based on TDP or average power draw, and give a little bit more, so what you'd roughly need for hardware.