Overkill psu trend?

[Qwerty2323]

I m just wondering why many prebuilds and custom include psu that have way more W than needed?

Does it relate to psu aging or something like that?

[Oshino Shinobu]

It's probably a matter of them covering themselves, or trying to avoid people telling them that the PSU is too small. (I get a lot people telling me my PSU isn't enough for my system at non-tech forum places)

 

A lot of GPUs say that they require 600W minimum, when they can often be run on 450W PSUs just fine. 

[Benergy]

I m just wondering why many prebuilds and custom include psu that have way more W than needed?

Does it relate to psu aging or something like that?

Might simply be better profit margins.

Or a marketing technique for a 'look at all the big numbers' kind of approach.

[Sir Asvald]

I m just wondering why many prebuilds and custom include psu that have way more W than needed?

Does it relate to psu aging or something like that?

People usually get them for future SLI, Crossfire. It's also a good thing to have 100W+ if you're going to overclock your system for extra headroom. 

[That_Random_Guy]

In my case it was because why not lol though i may sli in the future

[EthanTheFrogMan]

Might simply be better profit margins.

Or a marketing technique for a 'look at all the big numbers' kind of approach.

also there have been some really good deals on higher watt PSU's, so you might as well get a 750w vs a 500w if they are the same price and the same company

[BoredErica]

I think if the PSU is way overkill for your build, the PSU fan might not ever need to be on. Makes my PC quieter.

[TymmVonD]

Those 80+ ratings are based on 50% load. I always recommend double the wattage. Don't want to stress the psu and it take the mobo or storage out with it.

 

I recently try to keep in mind that tech is getting more efficient. But, it's still nice to have it when an opening in your budget looks good for SLI.

[QueenDemetria]

I m just wondering why many prebuilds and custom include psu that have way more W than needed?

Does it relate to psu aging or something like that?

Its easier to mass produce a computer with big PSU's, rather than make some with small PSU's and some with big PSU's. It also gives the owner more flexibility if they choose to upgrade GPU's and/or CPU's later on.

 

 

It also helps with warranty. If a PC model only has one PSU wattage then its easier for the company to replace, but if it has 3 PSU sizes then there is a chance for confusion.

[vanished]

What prebuilt did you see that has an excessive PSU?  They're typically just barely enough and are really low quality at that...

[WoodenMarker]

or trying to avoid people telling them that the PSU is too small. (I get a lot people telling me my PSU isn't enough for my system at non-tech forum places)

^ This would be my guess. Most people don't know how much a system actually pulls. 

[The Official Czex]

I'll go mATX with another STRIX in the near future or go dual Pascal if I wait.

[FAQBytes]

I m just wondering why many prebuilds and custom include psu that have way more W than needed?

Does it relate to psu aging or something like that?

It allows for upgrades down the road, as a very good PSU will far outlast the build it is running.

[AnonymousGuy]

^ This would be my guess. Most people don't know how much a system actually pulls. 

Agree.  My experience is many people don't have a clue how much power their system actually needs, and hugely overestimate power consumption of components.  I was just checking the other night and I could reasonably fit a 5960X and GTX 780 in a 450W PSU...maybe even do a touch of overclocking too.

[Sakkura]

Those 80+ ratings are based on 50% load. I always recommend double the wattage. Don't want to stress the psu and it take the mobo or storage out with it.

 

Do you run Furmark + Prime95 constantly? Otherwise that's not the best way to get the most efficiency. Especially considering efficiency drops more towards lower loads than towards higher loads.

[vanished]

Do you run Furmark + Prime95 constantly? Otherwise that's not the best way to get the most efficiency. Especially considering efficiency drops more towards lower loads than towards higher loads.

Having it be efficient when under heavy load is more important than being efficient while idling since the amount of power saved (or lost) due to efficiency levels will be much greater during heavy load.

[Sakkura]

Having it be efficient when under heavy load is more important than being efficient while idling since the amount of power saved (or lost) due to efficiency levels will be much greater during heavy load.

 

But the most common load is going to be things like gaming or maybe transcoding a video, and power draw will be significantly lower there. So you're definitely better off, efficiency-wise, by not going massively overkill.

[vanished]

But the most common load is going to be things like gaming or maybe transcoding a video, and power draw will be significantly lower there. So you're definitely better off, efficiency-wise, by not going massively overkill.

lower than what?  Those are the kinds of things I'm referring to as a "heavy load".  And yeah , you don't want a 800 W supply for a system with no GPU and a 20 W CPU, but if your typical draw during those "heavy load" activities (the ones you mentioned) is, say, 400 w, then 800 (or maybe a little less) would be reasonable, at least if top efficiency is your primary concern.

[Sakkura]

lower than what? Those are the kinds of things I'm referring to as a "heavy load". And yeah , you don't want a 800 W supply for a system with no GPU and a 20 W CPU, but if your typical draw during those "heavy load" activities (the ones you mentioned) is, say, 400 w, then 800 (or maybe a little less) would be reasonable, at least if top efficiency is your primary concern.

But if the power consumption in regular things like gaming is 250W, getting an 800W power supply because the system can pull 400W at max load is not a good idea.

[vanished]

But if the power consumption in regular things like gaming is 250W, getting an 800W power supply because the system can pull 400W at max load is not a good idea.

No it wouldn't be 250w - I specifically specified that hypothetical scenario at 400w

[Sakkura]

No it wouldn't be 250w - I specifically specified that hypothetical scenario at 400w

Fine, then max power draw would just be that much higher too. 550W? So then you'd be going for a 1200W power supply (since 1100W isn't common AFAIK).

[vanished]

Fine, then max power draw would just be that much higher too. 550W? So then you'd be going for a 1200W power supply (since 1100W isn't common AFAIK).

no I'd be going for 800.  where are you coming up with these numbers?  It's very simple: look at what your system will draw under a typical heavy load (not max - just what it would probably draw during gaming) and double it.  That would be the size of a PSU that will run your system very efficiently.  Do you need that much?  No, but we are just talking efficiency, and at any rate, it leaves you room to upgrade.

[WoodenMarker]

lower than what?  Those are the kinds of things I'm referring to as a "heavy load".  And yeah , you don't want a 800 W supply for a system with no GPU and a 20 W CPU, but if your typical draw during those "heavy load" activities (the ones you mentioned) is, say, 400 w, then 800 (or maybe a little less) would be reasonable, at least if top efficiency is your primary concern.

Gaming and transcoding video won't pull as much power as benchmarks like Furmark or Prime95--most things don't pull that much. 

http://evanmills.lbl.gov/pubs/pdf/Taming-the-Energy-Use-of-Gaming-Computers.pdf

From the article on gaming computers^: 

The mode-weighted average power draw during on time with a 5820k and gtx 970 with different modes of operation based on the average gaming computer was 212w and peak in gaming-mode was 512w. 

From this, the roughly estimated most efficient size of a psu for the above specs could be 424w if the peak efficiency is at 50%.

Also, after doing some very rough calculations on paper using the numbers above and the cx500 and a theoretical cx'1000' with the same efficiency curve, average US electricity cost of 12cents per kWh, the difference between the two per day would be 17582.05w a year or $2.11 a year. Keep in mind, I'm using some exaggerated numbers so the actual difference might be less.

TL; DR: The difference is very small. Save your money and get a smaller psu.

[vanished]

Gaming and transcoding video won't pull as much power as benchmarks like Furmark or Prime95--most things don't pull that much. 

 

I know.  That's why I'm saying rate the PSU based on gaming load, not super stress testing mode.

 

 

... and peak in gaming-mode was 512w. 

From this, the roughly estimated most efficient size of a psu for the above specs would be 424w if the peak efficiency is at 50%.

 

Can your please clarify?  It sounds like you are saying the idea PSU for a system that draws 512 watts while gaming is 424 watts...

[WoodenMarker]

I know.  That's why I'm saying rate the PSU based on gaming load, not super stress testing mode.

Can your please clarify?  It sounds like you are saying the idea PSU for a system that draws 512 watts while gaming is 424 watts...

424w was drawn from the mode-average load per day being 212w and the 50% peak in most psus. It's not an actual recommendation. 

I then made some calculations on paper and due to the results, I'd say the ideal psu would be the cheapest one available that is enough for the system.