Wattage Overkill

[sbazzle]

I'm curious what all your opinions are on getting a power supply with wattage that is above and beyond what would ever be needed for the system it's running.

Say I'm building a system that uses 500 watts total in its current configuration. Keeping any future additions to the system in mind, what would be considered overkill? A 650 watt PS? 750? 1000? 1500?

 

[Zap]

There's no hard numbers on that, but only you will know what you are likely to upgrade to in the future and how long you'll keep that PSU.

 

[Fullmetal Chocobo]

My opinion on it is that even if the PSU is 1,000 watts over the load, it will still run. It will not run if it is under the load however. I've had horrible power supply issues (with my dual Xeon 2.66--it was a nightmare having RAID 5 arrays go down due to power issues), so I prefer to give ample room just in case.

EDIT: I have a Corsiar 620w for this machine. My next machine is a dual quad core Xeon, and it will have one, possibly two, kw PSUs if needed. My ideal range is between 50-70% load, never above 75%. Best thing to do is have a Kill-o-watt or Power Angel and actually see what your load is (granted that is coming from the wall, but still, it is something to work with).

 

[biostud]

I'm pretty sure that a system with a quad-core, a single videocard and a couple of harddrives etc. will need no more than a 600w PSU for the next couple of years, but once you starts adding videocards your needs for more wattage goes up.

 

[Peelback79]

"Overkill" is purely subjective. In my eyes having a car that does 220mph is overkill. To someone else it's a necessity and for a lucky few drivers it's an occupation. You have to iron out the specifics or it's all just subjective. Are you going to keep the psu and case and upgrade compnents? Or, when it's all obsolete, just buy a new computer? Are you planning to last 2 years or 4 years? Do you play demanding games or are you just trying to get 500 fps on Minesweeper?

The only thing I'll recommend is don't by something because it's cheap. Sacrificing quality for quantity is not a good thing especially when it comes to putting some serious money into a compy.

For my computer, a high quality 600W psu would more than foot the bill. But I plan to stay current on the latest and greats GPU's as they come out and I wanted to have some breathing room because graphics cards are certainly not consuming less power these days. Plus, if your psu is not running maxed out, it will run cooler and more effecient.

 

[JEDIYoda]

Is there such a thing as over kill?

No as long as whatever you have will run whatever you have.....

Things that make you go hmmmm

 

[DSF]

Out of my own curiosity, what system are you planning to build that uses 500W? Or is that a purely hypothetical number?

 

[tenax]

Originally posted by: JEDIYoda
Is there such a thing as over kill?

No as long as whatever you have will run whatever you have.....

Things that make you go hmmmm

a good question and i think most would think get the biggest supply you can afford for future proofing (and very good quality supply). the issues i see are power consumption/heat/utility expense. i have a 500 watt silverstone (same as the famed seasonic) and i run a 7900gs, highly overclocked 6400, 4 gigs of ram, dvd burner, 3 hard drives, 5 usb devices and not a burp. if i were to bump up to 2 vid cards, i'd likely try my 500, but be ready to buy a 600ish ps. my "standard" used to be to buy a 400 watt range ps and never had a problem with various configurations. in light of more hd's and usb devices, i've upped that standard to 500..if i can find it and get into dual cards, my next standard will be about 600. these days when we seem to be running more ps'es 24/7, a person can't discount the cost of the difference of operating a 400 or 500 watt ps vs a 750+. and the potential heat you throw into your case as well the bigger you go.

 

[DSF]

Originally posted by: tenax

Originally posted by: JEDIYoda
Is there such a thing as over kill?

No as long as whatever you have will run whatever you have.....

Things that make you go hmmmm

a good question and i think most would think get the biggest supply you can afford for future proofing (and very good quality supply). the issues i see are power consumption/heat/utility expense. i have a 500 watt silverstone (same as the famed seasonic) and i run a 7900gs, highly overclocked 6400, 4 gigs of ram, dvd burner, 3 hard drives, 5 usb devices and not a burp. if i were to bump up to 2 vid cards, i'd likely try my 500, but be ready to buy a 600ish ps. my "standard" used to be to buy a 400 watt range ps and never had a problem with various configurations. in light of more hd's and usb devices, i've upped that standard to 500..if i can find it and get into dual cards, my next standard will be about 600. these days when we seem to be running more ps'es 24/7, a person can't discount the cost of the difference of operating a 400 or 500 watt ps vs a 750+. and the potential heat you throw into your case as well the bigger you go.

But a 750W PSU doesn't pull more power from the wall to power a given system than the 500W does. They both pull whatever they need, taking into account their respective efficiencies, to supply power to the system.

 

[tenax]

tres true..but if you're using that power... i guess my point is the car engine analogy..get the biggest car engine you can find to have that reserve..and it's going to be costly in a number of different ways

 

[DSF]

Originally posted by: tenax
tres true..but if you're using that power... i guess my point is the car engine analogy..get the biggest car engine you can find to have that reserve..and it's going to be costly in a number of different ways

But if you agree that what I said is true, then it's not costly in a number of different ways. The only extra cost is the initial purchase price of the higher-wattage unit.

 

[JEDIYoda]

Originally posted by: DSF

Originally posted by: tenax
tres true..but if you're using that power... i guess my point is the car engine analogy..get the biggest car engine you can find to have that reserve..and it's going to be costly in a number of different ways

But if you agree that what I said is true, then it's not costly in a number of different ways. The only extra cost is the initial purchase price of the higher-wattage unit.

exactly!!!

 

[Puffnstuff]

Wattage can be deceiving so look hard at the amps available on each rail. I chose to have excess capacity when I bought my current ps which means that it will not have to struggle to power my system. My apc battery backup has an lcd display which shows me how much load is being pulled from the wall and I'm not even using half capacity. With that said I also have exceptional overhead room for expansion should I choose to do so. I would rather have excess capacity than to need it and not have it. It's sort of why I drive a crew cab truck with a dohc v8. She just purrs along most of the time however when I need to go right now I know I've got it on tap.

 

[jonnyGURU]

Originally posted by: tenax
i have a 500 watt silverstone (same as the famed seasonic)

There are no Seasonic built SilverStones.

And there is no such thing as PSU overkill. A PSU puts out only as much as demanded of it, so it's really just a matter of how much you want to spend.

 

[tomoyo]

Most of the overkill is paying too much when you can pay a lot less and get a quality psu still. Also you may have a psu that is larger and could have a cooling system that is noisier than you want...although for a good psu, the system will just run the fan at an extremely low speed. As long as the psu is high efficiency across the 20-100% area, the power usage difference will be minimal no matter how big the psu is.

 

[etech]

Originally posted by: DSF

Originally posted by: tenax
tres true..but if you're using that power... i guess my point is the car engine analogy..get the biggest car engine you can find to have that reserve..and it's going to be costly in a number of different ways

But if you agree that what I said is true, then it's not costly in a number of different ways. The only extra cost is the initial purchase price of the higher-wattage unit.

I don't remember the exact breakpoints but a power supply is more efficient when it is running between ~50-75%.(Don't quote or hold me to those numbers but the gist of the statement is true)

The lower % of its output that it runs the less efficient a power supply is.

 

[DSF]

Originally posted by: etech

Originally posted by: DSF

Originally posted by: tenax
tres true..but if you're using that power... i guess my point is the car engine analogy..get the biggest car engine you can find to have that reserve..and it's going to be costly in a number of different ways

But if you agree that what I said is true, then it's not costly in a number of different ways. The only extra cost is the initial purchase price of the higher-wattage unit.

I don't remember the exact breakpoints but a power supply is more efficient when it is running between ~50-75%.(Don't quote or hold me to those numbers but the gist of the statement is true)

The lower % of its output that it runs the less efficient a power supply is.

This depends quite a bit on which power supply you're talking about. Power supplies which meet the 80Plus specification are 80% efficient or better all the way down to 20% load.

 

[jonnyGURU]

Originally posted by: DSF

Originally posted by: etech

Originally posted by: DSF

Originally posted by: tenax
tres true..but if you're using that power... i guess my point is the car engine analogy..get the biggest car engine you can find to have that reserve..and it's going to be costly in a number of different ways

But if you agree that what I said is true, then it's not costly in a number of different ways. The only extra cost is the initial purchase price of the higher-wattage unit.

I don't remember the exact breakpoints but a power supply is more efficient when it is running between ~50-75%.(Don't quote or hold me to those numbers but the gist of the statement is true)

The lower % of its output that it runs the less efficient a power supply is.

This depends quite a bit on which power supply you're talking about. Power supplies which meet the 80Plus specification are 80% efficient or better all the way down to 20% load.

Exactly. Many try to make this an apples to apples comparison, but it's often not.

An 80 Plus PSU needs to be 80% and up efficient at 20%, 50% and 100%. But a few are still efficient at loads < 20% and when they do drop below 80% efficiency, they're still about 78% to 79%, so the actual money saved in only about a quarter a year.

 

[Zap]

Originally posted by: Peelback79
"Overkill" is purely subjective. In my eyes having a car that does 220mph is overkill. To someone else it's a necessity and for a lucky few drivers it's an occupation.

:thumbsup: Great analogy!

Originally posted by: tenax
a good question and i think most would think get the biggest supply you can afford for future proofing

:thumbsdown: "Future proofing" is a fallacy, IMO. With computer gear, pretty much sooner or later something is outdated. Also, most prices go down (well, except for video cards and PSUs). So, to me "future proofing" is the act of paying a lot extra right now to save you from paying a little extra in the future.

The other thing is that technology changes. Sooner or later you'll run out of adapters or the changes become so fundamentally different that you will have to purchase a new item. Or, something "more popular" or drastically better comes out.

What if someone tried to "future proof" their motherboard purchase by going with socket 775 before Core 2 Duo came out because they heard Intel was going to make a better chip for the same socket, but didn't find out that their board can't support the new chips electronically? What if someone tried to "future proof" their PSU purchase a few years ago by getting something totally awesome... that didn't have PEG connectors or 8 pin +12v?

I'm not saying to totally ignore expected future developments. I'm just saying that the future is a lot shorter than most people think it is. Remember, it has been said that computer parts have 6 month generations. Your purchase today for a computer 3 years down the line would make it 6 generations old.

Originally posted by: jonnyGURU
And there is no such thing as PSU overkill. A PSU puts out only as much as demanded of it, so it's really just a matter of how much you want to spend.

There is, however, such a thing as an efficiency curve, and using 10% of a PSU's capacity usually isn't at that peak.

Originally posted by: tomoyo
Also you may have a psu that is larger and could have a cooling system that is noisier than you want...

Good point. I've had that problem. In my possession are an Antec Quattro 850W and a Silverstone 750ZF. I consider both to be too noisy to use in my "main" rig, which is currently using an Earthwatts EA500. Not the quietest, but a sight more quiet than the other two.

 

[tomoyo]

I would never ever ever recommend someone replace a psu because of this; but generally on psu tests, most psus seem to have a maximum efficiency around the 40-60%. However the difference is only around 2-5% efficiency...which amounts to probably pennies per month. It's a far larger waste of money, power, environmental resources to replace a psu. Stick to what works and replace only as needed.

 

[JEDIYoda]

Originally posted by: tomoyo
I would never ever ever recommend someone replace a psu because of this; but generally on psu tests, most psus seem to have a maximum efficiency around the 40-60%. However the difference is only around 2-5% efficiency...which amounts to probably pennies per month. It's a far larger waste of money, power, environmental resources to replace a psu. Stick to what works and replace only as needed.

I doubt that....any links...your own personal testing.....

 

[Martimus]

Originally posted by: Zap

Originally posted by: tenax
a good question and i think most would think get the biggest supply you can afford for future proofing

:thumbsdown: "Future proofing" is a fallacy, IMO. With computer gear, pretty much sooner or later something is outdated. Also, most prices go down (well, except for video cards and PSUs). So, to me "future proofing" is the act of paying a lot extra right now to save you from paying a little extra in the future.

Yeah, but the PSU is something that everything in your computer needs. If you update anything on your computer instead of building a whole new system, you are going to change the load on that PSU. I can understand just buying what you need on all of your peripherals and the CPU and GPU, because you can always drop in something else down the road if you need it, but the PSU is used to power everything, and the MB is used to integrate everything, so those are the two parts you really do want to overkill a little bit on. That way you are less likely to need to purchase two or three parts just to upgrade one component on your system. (Buying a new MB to update the processor, buying a new PSU to update the GPU or add additional drives).

 

[MrOblivious]

Originally posted by: JEDIYoda

Originally posted by: tomoyo
I would never ever ever recommend someone replace a psu because of this; but generally on psu tests, <<<most psus seem to have a maximum efficiency around the 40-60%. However the difference is only around 2-5% efficiency...which amounts to probably pennies per month. It's a far larger waste of money, power, environmental resources to replace a psu. Stick to what works and replace only as needed.

I doubt that....any links...your own personal testing.....

You doubt incorrectly

http://www.hardocp.com/reviews...BQU1UsaGVudGh1c2lhc3Q=

And since you have issues with me

http://www.80plus.org/manu/psu/manu_psu.htm

 

[JEDIYoda]

Originally posted by: MrOblivious

Originally posted by: JEDIYoda

Originally posted by: tomoyo
I would never ever ever recommend someone replace a psu because of this; but generally on psu tests, <<<<most psus seem to have a maximum efficiency around the 40-60%. However the difference is only around 2-5% efficiency...which amounts to probably pennies per month. It's a far larger waste of money, power, environmental resources to replace a psu. Stick to what works and replace only as needed.

I doubt that....any links...your own personal testing.....

You doubt incorrectly

http://www.hardocp.com/reviews...BQU1UsaGVudGh1c2lhc3Q=

And since you have issues with me

http://www.80plus.org/manu/psu/manu_psu.htm

Actually the older PSU`s I could see where that could true.
But you show me where a newer PSU made by Seasonic oe even the newer Antec PSU`s are anywhere close to being 40% to 60% efficient?
Don`t try because we both know that you would have get a brand that is barely recognizable or you would have to dig up a 650 watt OKIA...so you reallu want to go there??

Probably not...
Then we get to the 80plus issue....
This is taken directly from this thread-- posted by JonnyGURU--

Exactly. Many try to make this an apples to apples comparison, but it's often not.

An 80 Plus PSU needs to be 80% and up efficient at 20%, 50% and 100%. But a few are still efficient at loads < 20% and when they do drop below 80% efficiency, they're still about 78% to 79%, so the actual money saved in only about a quarter a year.

As has been said on Jonnys site many times a PSU rated 80plus will save you how much money over say a year?
At best an insignificant amount.

*******


So withy that said-- it could be said that 80plus is a real good thing but there are manyPSU`s that are rated in the 78% - 79% areas...I would even go so far as to sasy lets frop it down to 75%...again unless you fo to extremes tomoyo`s assertion that most psus seem to have a maximum efficiency around the 40-60%...is a little melodramatic shall we say? As is the significance or the importance of buying ONLY PSU`s that are 80plus certified!!


But whats the point of involking the 80plus org site....
"The 80 PLUS performance specification requires power supplies in computers and servers to be 80% or greater energy efficient at 20%, 50% and 100% of rated load with a true power factor of 0.9 or greater. This makes an
80 PLUS certified power supply substantially more efficient than typical power supplies and creates a unique market differentiation opportunity for power supply and computer manufacturers."


What exactly does 80plus mean.....that is highly significant in this case?
Think about it-- 80plus does not adress quality or workmanship or for that matter for what length of time a 80plus rated PSU will maintain that rating over time.
80plus is just that 80plus.....a good siye and a great standard to shoot for. Yet the bottom line is it means diddly in the big scheme of things....
For starter 80plus doesn`t test for free....
Then what do you say to the person whose PSU is say 73% efficient verses 80% efficient.
You sat nothing because in the scheme of things it`sa insignificant.
Then you have PSU`s that are rayed 80plus and you know know I am correct that in testing done by other sites they are over just barely under 80plus....so that really means not a whole lot.
Not enough to use that site as my only criteria for purchasing a PSU!!

To be rated 80plus you have to meet certain criteria yet with that said ther are many many perfectly good PSU that don`t meet that criteria!

Oh,,,and Thank for reminding me that I have issues with you -- Paul Johnson
HardOCP PSU Editor aka -- MrOblivious :laugh:

 

[MrOblivious]

Originally posted by: JEDIYoda

Originally posted by: MrOblivious

Originally posted by: JEDIYoda

Originally posted by: tomoyo
I would never ever ever recommend someone replace a psu because of this; but generally on psu tests, <<<<<most psus seem to have a maximum efficiency around the 40-60%. However the difference is only around 2-5% efficiency...which amounts to probably pennies per month. It's a far larger waste of money, power, environmental resources to replace a psu. Stick to what works and replace only as needed.

I doubt that....any links...your own personal testing.....

You doubt incorrectly

http://www.hardocp.com/reviews...BQU1UsaGVudGh1c2lhc3Q=

And since you have issues with me

http://www.80plus.org/manu/psu/manu_psu.htm

Actually the older PSU`s I could see where that could true.
But you show me where a newer PSU made by Seasonic oe even the newer Antec PSU`s are anywhere close to being 40% to 60% efficient?
Don`t try because we both know that you would have get a brand that is barely recognizable or you would have to dig up a 650 watt OKIA...so you reallu want to go there??

You have got to be kidding me. He is talking about they peak in efficiency be tween 40% and 60% load.