[SOLVED] Are PSU 80+ ratings a marketing gimic, or do they actually make much of a difference?

[DogNamedNibbles]

So I've been looking to replace my PSU, and have been wondering if the 80+ ratings are a marketing gimic, or not? I've searched what they do, but if the air it flowing straight out the case, do these even make much of a difference?

I'm mainly looking at 80+ White vs 80+ Gold.

(Side Question: If they do make a difference, would it be better to get a Cooler Master 80+ White, or an EVGA 80+ Gold? (I've heard cooler master's are extremely good, but canb't find much about EVGA))

 

[BogdanH]

My take on this..
Years back I had a cheap 600W PSU (I think it was LC-Power). I never have some power hungry system, so it was more than enough power wise. And it worked fine until upgraded mobo/CPU, which again was of similar power draw. What happened?
Everything was working fine.. the problem was, when I turned PC off, it went back on -similar as reset. To keep story short, PSU had poorly designed +5VSB circuit. By saying poorly, I mean, +5VSB current was within specs (to keep PC in standby). The problem was, it couldn't handle (short peak) current needed to switch into standby mode -at that point +5VSB voltage dropped and PC went back to power on state.
That said, PSU quality is more than power spec and 80+ rating. Since then I only buy brands with good reputation and never cheapest among them.

 

[jtk2515]

Currenly my budget is in the range is ideally capped at £150 NZD (£75 GBP, or $100 USD), but I'd be willing to go higher.

Currently I have:

EVGA GTX 1080TI
i5- 9400f (6 core, 3.8GHz - 4.1GHz)
16GB (2666 - 3000MHz)
3x SATA3 2TB
1x SATA3 SSD 500GB
(Don't think they use much, but I have 7x 120mm fans)

That's the main.

Your system is like 450-550watts if i calculated it correctly. So it would be loaded ~70-80%. The 700 watt evga gold will work fine.

 

[Deleted member 2720853]

The more efficient (higher 80+ rating) a PSU is = the less watts it'll draw from the wall and the less heat it'll give out. Rating has nothing to do with build quality, although a high 80+ rating shows that the components inside the PSU are capable of generating such efficiency. 80+ Bronze is the bare mnimum I'd say.

EVGA (avoid BQ and BR), Seasonic & Corsair (avoid VS) all make great PSUs. I have a Seasonic Prime PX-750 80+ Platinum in my system which is really a renamed Prime Ultra 750W Platinum, which is a top tier PSU. Noticing less power draw from the wall compared to my 80+ Bronze CX 650.

 

[hotaru.hino]

Having an efficient power supply means that the PSU has less waste heat to deal with, which in turn should help with the longevity and reliability of the PSU. But as said before, 80PLUS not an indicator of quality.

Lower wattage supplies may have lesser ratings if they're rated at all because the effort and perhaps expense of parts to get higher efficiency doesn't make up for the savings and the amount of waste power doesn't generate a lot of heat. It matters more on higher wattage supplies when they can be dumping well over 50W if pushed hard enough.

 

[Karadjgne]

View: https://m.youtube.com/watch?v=f6snWfd1v7M


This video makes a point. The underlying reasoning that using a severely overpowered psu just to stay inside ability is sledgehammer thinking. Grandpas around the world will always tell you to use the right tools for the job. Using a sledgehammer to drive a nail into drywall, just so you don't have to hit it as hard, isn't using the right tool. It'll work, until it doesn't, the end result being lack of control over the hammer and the resulting massive hole in the wall.

Using a 600w+ cheaply built and under protected psu with questionable reliability just to stay under 50% loads is sledgehammer mentality. Bigger does not mean better, or everybody should just buy the absolute cheapest possible 1000w psu and call it good.

 

[jtk2515]

View: https://m.youtube.com/watch?v=f6snWfd1v7M


This video makes a point. The underlying reasoning that using a severely overpowered psu just to stay inside ability is sledgehammer thinking. Grandpas around the world will always tell you to use the right tools for the job. Using a sledgehammer to drive a nail into drywall, just so you don't have to hit it as hard, isn't using the right tool. It'll work, until it doesn't, the end result being lack of control over the hammer and the resulting massive hole in the wall.

Using a 600w+ cheaply built and under protected psu with questionable reliability just to stay under 50% loads is sledgehammer mentality. Bigger does not mean better, or everybody should just buy the absolute cheapest possible 1000w psu and call it good.

It's a 35$ power supply. You can Makes jokes all you want, But for the price it is a very good power supply. Does not fail at 100% load and has a Good ripple Profile. That being said The reason I would keep it under 300watt is because of the amount of heat it will produce because it is a 80 white. If you have a 500watt load on a 80 white PSU it will produce 100watts of heat inside that small atx form factor. 100watt will require some serious cooling and some of the heat will radiant into your PC case Air supply. So for higher Wattages I would get a higher rated PSU.

Also depending on the model the PSU and case you would be trying to cool the PSU with preheated air. Like if you have a bottom mount PSU that is pulling air off the GPU or top mount. So if you have a 350 watt GPU then a PSU pulling air off the GPU trying to dissipate 100-120watts the PSU will not last very long.

Or if you choose you can discharge your PSU into your case then you would be putting all that heat onto your GPU and CPU.

600w load 80 white = 120watts of heat
600w load 80 bronze = 90 watts of heat
600w load 80 Gold = 60 watts of heat.

 

[Karadjgne]

But for the price it is a very good power supply.

That's the point. It's not a very good psu at any price. A pile of junk is a pile of junk. Doesn't matter if it's $90 or free.

If you have a 500watt load on a 80 white PSU it will produce 100watts of heat inside that small atx form factor.

No. Heat goes out the back. For all intents and purposes heat produced and it's affect on the pc is moot, the heat produced only affects 2 things. The efficiency of the psu as regards to its load and thermal capacity and the amount of electricity pulled from the wall and converted to wasted energy.

That Evga is tested/certified to maintain its rated output under loads at upto 40°C. At higher than 40°C it looses efficiency as wasted heat cannot be compensated for, which raises amperage use as resistance goes higher, which raises temps and on and on until the amperage use exceeds the psu ability to function. OCP protections are supposed to limit the current capacity and shutdown the psu should the draw become excessive. Many low grade psus have OCP (if it's there) set for such high limits that the psu literally burns up before reaching that trip point. And not having OTP results in no possible way for temps to not go higher.

Or if you choose you can discharge your PSU into your case then you would be putting all that heat onto your GPU and CPU

Psu exhaust is out the back. Fan pulls air into the psu from the top/bottom. Impossible to mount the psu backwards on a bottom mount case as the wiring is opposite the exhaust. It's only on rare cases with a side mount centered psu that exhaust could possibly turned interior.

V=IR. As amperage and resistance increases, voltage output is increased. Except voltage is regulated to a constant (±). That means voltage outputs are siphoned off as excess heat, which raises the temp inside the psu, which increases inefficiency, which increases impedence and or amperage. This'll happen upto a point at which you get 'run away', after which there's no stopping the process without pulling the plug. Protections in a psu are there primarily to stop run away, lack of protections means the process happens and the psu burns up (even catching on fire) before you realize there's an issue.

 

[Deleted member 2720853]

Honestly I'm impressed more now with that evga 500w after this review. It's in the 30-37$ range. Has less then 100mv of ripple at 100% load and 19mv of ripple at 60% load. For the price the 600w and 500w seem like awesome PSU's. Would you not recommend these as budget options for a 250-300 watt load?

No I would not. I'd rather recommend a CX550M/CX 650 as the bare minimum of budget when it comes to PSUs. Don't skimp. You'll have buyers remorse and possibly a dead card later.

A garbage PSU is a garbage PSU, easy as that.

 

[DSzymborski]

It's a 35$ power supply. You can Makes jokes all you want, But for the price it is a very good power supply. Does not fail at 100% load and has a Good ripple Profile. T

You keep using the word "good" but I do not think the word means what you think it means.

"ATX spec" is extraordinarily lax. It's just the line for the most rudimentary thing you can call a power supply. It's not used as a recommendation guideline by anyone competent.

Do you go on car forums and suggest people source tires for their new sports cars from the city dump? "Make jokes all you want, but you can't find a better tire for five bucks a wheel!" This is a $400 GPU we're talking about, not a GT 710 thrown into an FX-4300 prebuilt. Don't recommend people skimp on safety items, unless you intend to warranty their purchase. Do you intend to do so?