How much is a % of psu efficiency worth in £(and noise)

ginjaninja · 9 Nov 2013 at 08:36

PC Type - Media server / HTPC / Gaming
Spec
Overclocked Haswell i7 4-4.5 ghz. 4 Ram sticks. 10x3tb Green HDDs, 1x SSD,GTX780. COSMOS II, 5 Fans, PSU?
HDDs are sata motherboard attached individually so can power down when not in use.

Usage - on 24/7, watching media 1hr per day, Playing Games 1hr per day. (possibly 24/7 metric is the only significant one to keep simple)

Anticipated Lifetime - 10yrs

Priorities Highest 1st
Not spending money for no tangible benefit
Lifetime cost over cost of initial purchase
Quiet

Avg anticipated Cost per KWH over next 10 yrs=25p
Idle load=please suggest (GPU idle i understand is in order of 80W)

http://extreme.outervision.com/PSUEngine

suggests a 500W PSU but i understand a larger psu may be quieter under load but less efficient at idle. Maybe i need to look at psus that are very efficient at low loads (maybe all? or none? are any better or worse)

Has any one ever investigated/Can anyone suggest an appropriate power supply / suggest a calculation or result for annual value in a %of efficiency for the psu.

thank you

ginjaninja · 9 Nov 2013 at 09:14

Doomedspeed said:
With that rig, you need a good efficiency rating, This means the machine will always be stable and it'll never be drawing more than it needs to.

Also it'd be helpful to have a PSU with 'adaptive fan control', which means it is fanless when under very little strain, then the fan only ramps up when more power is drawn.

I would recommend this piece of kit:

YOUR BASKET
1 x seasonic 660w '80 plus platinum' modular power supply £129.95
total : £140.45 (includes shipping : £8.75).

thank you for your suggestion.
i can see how adaptive fan is relevant, i also know some parts dont turn on the fan at all at lower loads (but that might mean an overspecced wattage which i understand is the biggest enemy of value, so adaptive fan gets a +)

i also made a calculation/further assumptions for comment.
adding evidence as mentioned above efficiency might well be worth paying for when viewed over the longer term for an always on device

idle kw usage 0.125
hours in year 8760
annual kwh 1095
annual cost £274
80 gold over bronze @ 20% loading 7%
80 platinum over bronze @ 20% loading 9%
80 titanium over bronze @ 20% loading 13%
gold platinum titanium
annualsaving over bronze £19.16 £24.64 £35.59
over 10 years £191.63 £246.38 £355.88

strangley the psus in this review dont meet the standard listed on wiki for 20% load.
http://www.tomshardware.com/reviews/80-plus-platinum-power-supply-efficiency,3327-13.html
http://en.wikipedia.org/wiki/80_Plus#Efficiency_level_certifications

ginjaninja · 9 Nov 2013 at 10:28

joeyjojo said:
Your calculations look good.
It looks like they do to me. Platinum at 20% load need to be 90% efficient, which all those tested achieve?

thanks for advice,
so they do ...got my platinums and titaniums mixed up.

ginjaninja · 9 Nov 2013 at 10:43

OCers are not alone, no one sells titanium rated psus in uk, particularly relevant for always on users with larger psus given the mandated efficency at 10% load (the other standards dont specify at 10%)

ginjaninja · 9 Nov 2013 at 12:28

ThaReaperGuy said:
I may be missing something as I've just awoken but, is there much point of having it run 24/7 for you to use it for only 2 hours a day?

Its a media server, accessed by xbox, tv, tablets around the house, The house is 3 stories and i would hate to have to go up 2 flights (to switch on) just to watch media on tv downstairs. But maybe i should spend the money on a remote switchon function...anyone aware of the such a product, it would need to be accessible remotely over internet as i watch media when on the road as well.

I take the point about a 2nd rig, the 80W idle from the gpu blows away the benefit of improved efficiency psu when compared to a dedicated media server drawing significantly less at idle (assumed). Maybe i should be concentrating in this area if i had all the parts anyways.

What i really need is a gaming gpu which doesnt draw power in idle (assuming this is the lions share of the idle draw)..then i could stick with the one rig (which is what i really want)

ginjaninja · 9 Nov 2013 at 18:07

oceaness said:
I'm not sure how much of a power saving it offers because it would depend on whether the motherboard could completely shut down the discrete card when not in use.

http://www.lucidlogix.com/

interesting power\cost savings if it could, it would be ideal for this 24/7 application with the odd bit of gaming in a single rig; i cant find anything on the internet to verify it does. im not even sure if its a software or hardware solution.