Which power supply for this system?

[me-yeah]

if you take 20% of the watts away from 650 because it is only 80% efficient, you will be left with 530 watts

[pastymuncher]

You have got it the wrong way around. Efficiency is all about how much power the psu needs to draw from the wall to deliver the required output to the components.

[kalniel]

if you take 20% of the watts away from 650 because it is only 80% efficient, you will be left with 530 watts

As the post above this one, you've got it wrong way around - the rating shows what the PSU will supply to the components. The efficiency tells how much extra it will draw from the wall.

650W at 80% efficiency provides 650W, draws 813W from the wall
650W at 85% efficiency provides 650W, draws 765W from the wall
650W at 90% efficiency provides 650W, draws 722W from the wall.

Ie they all provide 650W.

[me-yeah]

pretty sure its the amount lost by transistors and non japanesse capacitors and all the electromagnetic fields in the PSU

[kalniel]

pretty sure its the amount loss by transistors and non japanesse capacitors

Eh? It's the amount lost by all the components regardless of nationality, between the wall and the DC provided to the computer.

[me-yeah]

higher price PSU`s will lay down that it has japanesse capacitors inside of them, along with most tech websites, lower loss gives them longer life etc

[kalniel]

higher price PSU`s will lay down that it has japanesse capacitors inside of them, along with most tech websites, lower loss gives them longer life etc

Can do, but they'll still provide the same 650W

[peterb]

higher price PSU`s will lay down that it has japanesse capacitors inside of them, along with most tech websites, lower loss gives them longer life etc

The 'losses' are those conversions that end up as heat. These are switching losses in semiconductor junctions, IR losses in wiring (exacerbated by poor power factor correction) relaxation dielectrics losses in capacitors (regardless of where their passport says they come from ) and magnetos friction losses in transformer cores.

Minimising these losses requires good circuit design and the appropriate components. Shottky diodes switch very fast with lower losses, switched mode PSUs operating at high frequencies with ferrite core transformers can minimises magneto-strict ice losses. High frequencies also enable lower value filter capacitors in the output stages, but can lead to higher dielectric losses.

There was a trend (dare I say hype?) that blamed PSU failures on poor quality capacitors, and it is true that they may be the component that fails. But the fact that a capacitor is Japanese is not a guarantee of quality, although it is true that some Brands of components (Panasonic, ITt) have good reputations.

But in a mass market commodity like a power supply, manufacturers are looking to shave the component costs to a minimum. If you are making 100,000 units a year, the shaving a penny off two or three components makes a significant difference to the production costs.

On the other hand, the component cost is a relatively small amount of the item cost. The rest is setting up the production line, design effort, quality control and quality assurance.

That is why many of the branded PSUs are outsourced for manufacture. The Company designs and gives the specification to the production company, who build to that spec, using the components specified.

There are far fewer manufacturers than there are brands being sold!

[ik9000]

japanese tantalum caps will (normally) last longer due to the stability of the electrolyte layer.

If you really want to read up on the standard for PSU efficiency however - and as ever - a good place to start is the wiki page. https://en.wikipedia.org/wiki/80_Plus

It confirms the above that efficiency is vs power from the wall, and also makes good points about power factors, and sub-20% load efficiency being allowed to be below par - something to remember for idle loads. Is there even a PSU out there that conforms with the one watt initiative? Be interesting to know that. It can't be possible surely - it would need more than 1w to hold a PC in sleep/hibernate?

[madmantheonlyone]

Even a 600W PSU would be able to handle that, but I wouldnt go below that

[me-yeah]

so the bottom line to most of this page, cheap PSU`s use cheap parts which make it less efficient, and the cheapest parts make it only 80% efficient and then it gets a bronze badge

ontop of that, your better off just getting a gold or platinum PSU, the extra money you spend on the PSU will pay for itself in no time with money off your electricity bill every month

[peterb]

Cheap PSUs may use cheap or less efficient components, and may not be optimally designed which may contribute to a low er efficiency rating. Worse though is that the regulation of the various lines may not be up to scratch, worse still, they may have inadequate overload or short circuit protection, so if the fail, they are more likely to take some other component with it.

Bottom line - don't skimp on the power supply.

japanese tantalum caps will (normally) last longer due to the stability of the electrolyte layer.

Japan doesn't have a monopoly on quality electrolytic capacitors!

[kalniel]

ontop of that, your better off just getting a gold or platinum PSU, the extra money you spend on the PSU will pay for itself in no time with money off your electricity bill every month

How much time, would you say? Say you do 2 hours of gaming a day perhaps.

[me-yeah]

How much time, would you say?

why would i know, depends if the PSU is in a NAS, or you have a bronze PSU and SLI/Crossfire and play games 8 hours a day with a 1200w PSU

[kalniel]

why would i know, depends if the PSU is in a NAS, or you have a bronze PSU and SLI/Crossfire and play games 8 hours a day with a 1200w PSU

I assumed you knew which is why you said it'd take no time at all.

Specs as per the original post, 650W bronze vs gold, 2 hours of gaming a day (at 300W load).

edit: Let's work through it then.

Electricity is 10p/kWh. 2 hours of gaming at 300W at 100% efficiency would be 6p. Bronze efficiency is 85% at 50% load so 7.059p. Gold is 90% @ 50% load, so 6.667p

So if using the PC for gaming like that, you'd save 0.392p a day, or 11.92p a month.

An Antec 650W bronze costs £51.18 at scan.
An Antec 650W gold costs £73.00 at scan.

Difference of £21.82.

Or 183 months.

Or 15.25 years.

Not quite 'no time at all'.

[abaxas]

Cheap PSUs may use cheap or less efficient components, and may not be optimally designed which may contribute to a low er efficiency rating. Worse though is that the regulation of the various lines may not be up to scratch, worse still, they may have inadequate overload or short circuit protection, so if the fail, they are more likely to take some other component with it.

Bottom line - don't skimp on the power supply.



Japan doesn't have a monopoly on quality electrolytic capacitors!

Price != quality. Cheap != bad.

TBH all PSUs tend to be built to a price and attacked by the bean counters. There simply isn't the market for quality as it's all done on price.