Worth it do downgrade power wattage?

[tigersty1e]

So I have a Corsair 520hx powering up:

Intel E6320 1.86GHz overclocked to 2.1 GHz @ 1.3 vcore
4gb ram running @ 600 mhz
AMD 6450
2 optical drives
1 ssd
1 500 gb hard drive


Yes, overkill. But the 520hx is efficient enough. If I were to go to a smaller psu how many less watts would I pull from the wall?

 

[TemjinGold]

Not enough to warrant the switch.

 

[BoT]

if you go with a low quality, lower wattage psu you might end up wasting more power.
the only lower one i might would consider switching to is the
CORSAIR Builder Series CX430 V2 (CMPSU-430CXV2) 430W ATX12V v2.3 80 PLUS

 

[tigersty1e]

if you go with a low quality, lower wattage psu you might end up wasting more power.
the only lower one i might would consider switching to is the
CORSAIR Builder Series CX430 V2 (CMPSU-430CXV2) 430W ATX12V v2.3 80 PLUS

with something like this, how much power would I save?

assuming i'm consuming 100 watts from the wall.

 

[BoT]

A handful at best I would say

 

[TemjinGold]

Like 3 watts.

 

[BoomerD]

You have an efficient power supply as is. Going with a smaller unit won't save much if anything.
It's not like the power supply provides a constant 520 watts whether your components use it or not. It only provides as much as the components need.

Yes, if you got a lower wattage unit that's as efficient as the HX520, it MIGHT have a slightly better efficiency curve at that power draw...but 3% of 100 watts is only 3 watts...so it'd take 333 hours to use one kilowatt. Assuming 15 cents/Kwh, that's $.00045/hr, so it would take something like 100,000 hours of use to pay for a $45 power supply...

 

[Zap]

You would probably save more power by switching to a Celeron G530 CPU and using integrated graphics than you ever would with even a 100% efficient PSU.

 

[jonnyGURU]

What Zap said.

 

[know of fence]

Nobody knows really (virtually nobody tests it low enough, rarely does Anandtech), even though most PCs are idle 95% of the time and well below 20% load that is used to label stuff "80 plus certified".
Instead you get inexplicably apologetic rationalizations how it doesn't matter when you divide 50W idle power by 0.8 or 0.7 PSU efficiency (62.5 vs 71 Watts resulting). I am extrapolating the red graph to get roughly those numbers. And those power curves when viewed from left to right rise quite significantly at low wattages, which makes choosing the right power envelope similarly significant.

It's just frustrating to see 15W powered down graphics cards and SpeedStep&#174;ed modern CPUs to those low marks, jsut to waste it all with the power supply on <10% load.

Googled: Power supply efficiency
stumbled upon your model. (presumably 110VAC)

Source:http://www.codinghorror.com/blog/2007/05/when-hardware-is-free-power-is-expensive.html

In this article from three years ago you can see the difference between 300W and 4xx Watt PSUs

http://www.anandtech.com/show/2624/5

 

[heymrdj]

Nobody knows really (virtually nobody tests it low enough, especially not Anandtech), even though most PCs are idle 95% of the time and well below 20% load that is used to label stuff "80 plus certified".
Instead you get inexplicably apologetic rationalizations how it doesn't matter when you divide 50W idle power internally by 0.8 or 0.7 PSU efficiency (62.5 vs 71 Watts resulting). I am extrapolating the red graph to get roughly those numbers. And those rise quite significantly at low wattages, which makes choosing the right power envelope similarly significant.

It's just frustrating to see 15W powered down graphics cards and SpeedStep®ed modern CPUs to those low marks, jsut to waste it all with the power supply on <10% load.

Googled: Power supply efficiency
stumbled upon your model. (presumably 110VAC)

Source:http://www.codinghorror.com/blog/2007/05/when-hardware-is-free-power-is-expensive.html

In this article from three years ago you can see the difference between 300W and 4xx Watt PSUs

http://www.anandtech.com/show/2624/5

I understand you like green about everything. I like to save watts too. But on your numbers that would be 38,461 hours (just shy of 4.5 years if you run 24/7) to break even on the cost of the new PSU. And that's just a 45$ unit. On top of that what about things besides your carbon footprint in terms of electricity. Efficiency would be using the old PSU until it dies and then recycling it, thus making the most out of the carbon produced to recycle the unit's various parts. If you take a perfectly good unit and recycle it, you've only broken down the footprint of producing the unit a littl ebit, and then you're already paying the cost of recycling it on top of the cost of the unit.

Right now energy production is pretty effiecient, not perfect, but pretty damn good. THere's other things to think of in the equation besides the energy cost.

 

[know of fence]

I just like to emphasize: that rules of thumb we learned about power supplies couple of years ago, do NOT apply today. Leaving 100&#37; headroom compared to actual load consumption, will rather than hitting the maximum of the power curve, miss efficient use for most of the time when the PC is idling. When the linked AT article was published video cards idle'd at crazy 50-100W, there was no auto-throttling of CPU speed, and "enthusiasts" insisted on putting fast spinning hard drives in RAID0. Today the red vertical bar (pic) showing the range of possible loads is stretched further to the left as far as 40 W in case of office PCs.

@heymrdj
Using the suggested 8.5W difference you calculate a 38461h break even, that makes for a kWh price of <14 cent, much too low I think. From the AT picture I read about 6W highest difference between between 450W and the smallest unit, but OP's PSU is 520W and bigger still.

Also you suggest replacing old PSU with 45$ junk, I'd never recommend that for anything but occasional use, especially not now when platinum rated units are available, pushing 90% efficiency. It doesn't matter what the brand is either. If it is from their bottom product line the PSU will likely have a crappy fan, buzzing coils and cheap caps. A 150$ PSU can be used for years to come long after the Core 2 duo is replaced.