[deleted]

[User5537135]

[deleted]

[WhitetailAni]

5 minutes ago, DrySoup said:

Surely if the pc isn't getting enough power, the pc can determine which are most essential and ration power out among them? Or at least let the user manually determine this? Where in its thought process does it decide to just fucking crash/fry? Let's say I have a working pc, but add a graphics card that exceeds the wattage of the psu, would the pc not just give it as much spare power as possible? While continuing to give full power to the other essential components?

Power supplies aren't smart.

They don't allocate power like PCIe lanes.

They just put power onto the different voltage rails which is then distributed via wires.

Adding a "smart" feature would most likely require a complete rework of how power supplies provide power, which would effectively kill backwards and forwards compatibility.

[Middcore]

9 minutes ago, DrySoup said:

Also, another thing. You know the way graphics cards have "recommended wattages", yeah? How the fuck do they know that when they don't know how much any of my other components consume? What are they basing this off? Is it just a fucking guess?

 

It is a conservative guess based on the fact GPU manufacturers know some people will use junk PSU's that don't actually make the wattage they claim...  so they err on the high side because they don't want, for example, some smoothbrain who bought a "650W" PSU that would struggle to make 500W on its best day to come crying to them when it can't supply enough juice for their shiny new GPU. 

 

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The amount of overthinking you have to endure just to not have a fucking housefire is astonishing.

 

Memes aside, even poor PSU's are unlikely to cause a house fire. That said, if you want a PSU that's reliable and unlikely to damage any of your other expensive components, you really can't go wrong by picking a unit with enough wattage for your parts (based on a calculator like PCpartpicker) plus ~25-33% headroom from Tier A or B on the list here on the forums. 

[flibberdipper]

I'll just break it down the way I see it.

 

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Surely if the pc isn't getting enough power, the pc can determine which are most essential and ration power out among them? Or at least let the user manually determine this? Where in its thought process does it decide to just fucking crash/fry? Let's say I have a working pc, but add a graphics card that exceeds the wattage of the psu, would the pc not just give it as much spare power as possible? While continuing to give full power to the other essential components?

Power supplies are generally dumb boxes of magic fairy sauce, they don't really have any idea where the hell power is going with just a few notable exceptions (such as the Corsair ones that can connect to iCUE and show you where the draw is). Now, let's say that they aren't dumb boxes and they had the ability to ration power. That comes with its own set of problems. Let's say we go with that GPU example, if it starts diverting power to the GPU when something else needs it (like a CPU), well now that part isn't getting enough power and is liable to cause a crash scenario.

 

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I know that higher quality PSUs tend to have cutoffs in place, but 1) why is this not a default thing? and 2) why does this often fry the psu?

Any PSU from a reputable seller should be able to do a clean cut and not shit its pants and yell "I'M BROKEY." If OCP kills a PSU, then clearly it's either 1) faulty or 2) a cheap/bad design.

 

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Also, another thing. You know the way graphics cards have "recommended wattages", yeah? How the fuck do they know that when they don't know how much any of my other components consume? What are they basing this off? Is it just a fucking guess?

These overly conservative estimates are just the manufacturers covering their asses. Which is better: Overdoing the recommendation, or not doing it enough to account for most setups and then having some dingus complaining that their 3080 and overclocked 9900K doesn't work with a 600W PSU? Hell, the 1050Ti has a recommended PSU of like 350W to cover their asses, yet I'm running mine on a 240W unit with TONS of room to spare.

[Lurick]

18 minutes ago, DrySoup said:

Like, it's 2021, is technology really this retarded still? If you're on a boat that's capsizing, wouldn't you rather toss someone out than destroy the whole boat and let everyone drown? I can understand this happening if you were to get a psu that stores too much energy, but no, that's considered a good thing apparently? Ah yes, you can store excess power all you want, even if you have nowhere to put it. That's totally fine. But as soon as one of your components isn't getting the most power possible, you piss and shit your pants? What the fuck? So you're telling me the psu is intelligent enough to not take more power than it needs, but isn't intelligent enough to ration out the power it has without going ape mode?

A PSU does NOT push power, power is drawn by the components. You would need a PSU that has a dedicated system inside to detect and communicate with each component in the entire system to do anything close to what you're asking for.

 

Maybe the fact that it's 2021 and people still think PSUs can make magic and expect them to wipe their butts is the problem?

[kelvinhall05]

Lol OP has literally no idea how electricity works.

 

 

Also $10 says he bought an inadequate PSU and blew up his PC, prompting this thread

[seon123]

28 minutes ago, DrySoup said:

Like, it's 2021, is technology really this retarded still?

Well, something is, and it's not technology. Also, language. You make yourself look like you are a 14 year old throwing a tantrum.

28 minutes ago, DrySoup said:

Surely if the pc isn't getting enough power, the pc can determine which are most essential and ration power out among them?

That's not how it works at all. The PSU supplies a constant voltage of 12V, 5V, 3.3V and -12V, and the components regulate the current.

28 minutes ago, DrySoup said:

Let's say I have a working pc, but add a graphics card that exceeds the wattage of the psu, would the pc not just give it as much spare power as possible? While continuing to give full power to the other essential components?

What would happen with any halfway decent PSU (and many garbage ones) is that they will safely shut down without damaging anything.

28 minutes ago, DrySoup said:

Yes yes yes yes yes, I KNOW that would be bottlenecking.

Well, that is completely wrong. So....

28 minutes ago, DrySoup said:

I know that higher quality PSUs tend to have cutoffs in place, but 1) why is this not a default thing? and 2) why does this often fry the psu?

It is a default thing, and it does not fry the PSU, unless the protections are set up improperly.

28 minutes ago, DrySoup said:

Is it just a fucking guess?

Yes

28 minutes ago, DrySoup said:

The amount of overthinking you have to endure just to not have a fucking housefire is astonishing.

If you find this difficult, I recommend finding an adult (or anyone knowledgeable over the age of like 12) to help guide you. While you're at it, look up anger management courses

[TetraSky]

31 minutes ago, DrySoup said:

Surely if the pc isn't getting enough power, the pc can determine which are most essential and ration power out among them? Or at least let the user manually determine this?

That's not how electronics work.... Or how electricity work.

 

The power supply is just there to... supply power that the device it is connected to demand. It's not "smart". It doesn't tell the PC how much power it can supply, nor can the PC tell its components to take up less power just because you didn't adequately choose a proper PSU (some laptops could potentially somewhat do this, because they are literally built from the ground up knowing full well which parts they have and how much power each parts consume +-5%, but a custom PC? NOPE).

 

A PSU takes AC from the wall, convert it to DC through diodes and capacitors, uses voltage regulators to limit the voltage to a specific one need by your device, etc etc... So yes, "technology" is still "retarded".

[User5537135]

[deleted]

[WhitetailAni]

Just now, DrySoup said:

Fair enough, though how would a 650W struggle to make 500W? Does that just happen over time?

The wattage rating can mean nothing.

Let's say we have a 1200w power supply.

It can supply 200w on the 12 volt rail, and 1000w on the 5v and 3.3v rail.

It's useless. There's no way to use 1000w on the 5v and 3.3v rail.

That's why. The wattage rating is the sum of all wattage on all three voltage rails, but if there is only 200w on the 12v rail it's useless because that can do CPU, motherboard, and maybe RAM.

[Archer42]

One funny thing though - all the trolling aside technically pc components already do something like this.

 

For example videocard measures gpu power consumption and limits boost frequencies based on that. And in can be controlled by software.

Same with motherboard/CPU.

 

Making both motherboard BIOS and videocard BIOS aware of PSU state would be relatively easy and would not require breaking compatibility, and then both components can be limited as needed... and it will work, because it will not be PSU which limits the power (where "it is not how electricity works" statement will be true), but consumers themselves will be reducing their "power limits" as requested.

 

In a sense it already works like this in laptops...

[flibberdipper]

2 minutes ago, DrySoup said:

What I was suggesting is some way for components that need to be at full power to be given it, and for other components to be essentially underclocked to the point of requiring an acceptable amount of power.

 

I don't really have much personal experience or empirical evidence, which is probably why looking into this is so frustrating. I can see something work fine for plenty of people but then there is one horror story of an entire PC exploding that sows doubt. Is the wattage consumption generally accurate or more ass-covering? It tends to be specific down to the watt from ones I've seen so that leads me to believe it is genuine.

That first point is theoretically possible, laptops sort of have their own spin on it now. It's just generally not needed in desktops as long as things are kitted out correctly and it would be a bit of a pain in the ass. That last point is probably why we just don't see it in the desktop space.

 

Almost universally the manufacturer recommendations are just ass-covering. There's obviously a few exceptions though, like the 750w recommendation for a 3090. That one makes a bit of sense, because at that point you're also likely going to have a power-sucker CPU so it wouldn't be unreasonable to have a system capable of slurping down 600 watts with everything tapped out.

[WkdPaul]

8 minutes ago, ragnarok0273 said:

The wattage rating can mean nothing.

Let's say we have a 1200w power supply.

It can supply 200w on the 12 volt rail, and 1000w on the 5v and 3.3v rail.

It's useless. There's no way to use 1000w on the 5v and 3.3v rail.

That's why. The wattage rating is the sum of all wattage on all three voltage rails, but if there is only 200w on the 12v rail it's useless because that can do CPU, motherboard, and maybe RAM.

this, I've seen it on real cheap units. They all have the same 12v rating, higher W units only have larger 5v and 3.3v.

[User5537135]

[deleted]

[User5537135]

[deleted]

[flibberdipper]

15 minutes ago, DrySoup said:

Also, when people say only shitty PSUs will fry, they just mean the brand not necessarily the price right? Like I'm considering upgrading a dell optiplex 7010 with a 240W PSU, fairly shit but Dell is seen as a reliable brand, at least safety-wise? Sorta off-topic but you said you upgraded a PC with a 240W PSU as well so.

More or less. Obviously even brands which are generally accepted as good (like EVGA) can have some pretty asscheese units and then cum zone units (like the N1 and T2 lines, for example). But even the N1 will be better than some Chinese special "800w 90+" unit you buy off AliExpress for 28 dollars.

 

And for what it's worth, Dell has had a good habit of putting pretty decent units in the OptiPlex line and their various gaming desktops (not super sure about Vostros or Inspirons but I believe even those use good ones). Hell, their older ATX PSUs from around 2005 or so are absolute behemoths.

 

The only OEM I can single out as consistently using trash outside of their absolute high-end would be HP. Hopefully they've improved since my last experience, though.

[Spotty]

1 hour ago, SGT-AMD said:

So, if you do the calculations, if the computer under full load draws 500w, I prefer to buy a psu of 1000W+.

More headroom equals less heat in the psu.

A 1000w PSU outputting 500w can be just as hot as a 500w PSU outputting 500w.

The heat generated in a PSU is due to the efficiency losses. If a power supply is 90% efficient then at 500w it's pulling 555w from the wall with the 55w difference being wasted as heat inside the PSU. Doesn't matter what the maximum rated wattage for the unit is.

[Kid.Lazer]

15 minutes ago, Spotty said:

A 1000w PSU outputting 500w can be just as hot as a 500w PSU outputting 500w.

The heat generated in a PSU is due to the efficiency losses. If a power supply is 90% efficient then at 500w it's pulling 555w from the wall with the 55w difference being wasted as heat inside the PSU. Doesn't matter what the maximum rated wattage for the unit is.

I think what he was getting at (although in a poorly worded way) is that he shoots for double the expected load so as to keep the PSU in its peak efficiency range which minimizes waste heat. Which, for those who don't know, is usually between 40-70% load, depending on the exact model.

 

[Mark Kaine]

17 hours ago, ragnarok0273 said:

Power supplies aren't smart.

They don't allocate power like PCIe lanes.

They just put power onto the different voltage rails which is then distributed via wires.

Adding a "smart" feature would most likely require a complete rework of how power supplies provide power, which would effectively kill backwards and forwards compatibility.

While that's maybe actually how it works right now, op is saying the motherboard - which ultimately requests the power should be the "smart" one - of course then you have stuff like gpus that pull power directly from the psu, they would then need to negotiate first with the mobo of its 'ok' to draw power now... lol don't get me wrong I don't agree with the op but that's how I understand their 'request'... 

 

 

Of course, ultimately that's already how it works - kinda - in the ideal case the psu will just shut down when something goes wrong, and hopefully quick enough so nothing gets damaged.