0PSU LogoEficiencia PSU: la pena el ascenso? parte 3

This is the third install­ment in a series of art­icles address­ing PSU effi­ciency. Art­icle one focused on a [int­link id=“76” type=“post”]nuevo servidor teórico[/intlink], art-ículo 2 en un [int­link id=“77” type=“post”]PC de escritorio típico[/intlink].  This art­icle will focus on a cur­rent real serv­er, and intro­duces a new PSU — an 80+ plat­in­um model.

The sys­tem spends a lot of time semi-idling (serving net­work and disk requests but not doing too much CPU trabajo).  I estim­ated that it would pull around 150W on aver­age, and then cal­cu­lated it below. It really did come out exactly like that!

Base sys­tem Sem­pron LE-1100 (1.9GHz de un solo núcleo) el 630i nForce / 7050 mother­board. 2Gb DDR-II35W
2x Sam­sung F4 2Tb HDDs, 7x 1 TB verde discos duros inc. WD Green 1 TB, Seag­ate 1Tb and Sam­sung 1Tb, 1x unidad 7200rpm WD 750 GB, 1x Max­tor 300Gb 7200rpm drive, 1x WD 200Gb unidad IDE 7200rpm108W
Areca 1220 RAID Tarjeta5W
2x 120 mm Caso Ventilador2W
TOTAL150W

Sin interes, assum­ing a cost of £0.10 per kWh this sys­tem would cost a total of £131.50 a year to run even with a per­fectly effi­cient PSU!

los ATX spe­cific­a­tion requires 70% effi­ciency. Below is a com­par­is­on between a bare min­im­um ATX PSU and a few highly effi­cient PSU'S.

The fig­ure for the gen­er­ic PSU is based on the min­im­um require­ment and is there­fore a worst case. I have cal­cu­lated a best-case yearly sav­ing, based on a kWh charge of 10p and assum­ing 24.7 usage.

Make / ModelEffi­ciency at 150WEst. C.A. poder de dibujoSav­ing
ATX 250w v2.2 ATX70% (a 150W)215W
Season­ic X‑40088.8%169W40.39 £
Cor­sair AX85087.4%172W38.02 £
Ener­max Modu87+ 500w88.5%169W39.89 £
Corsair CX400W82.1%183W28.31 £
Kingwin Lazer Platinum 550W93.3%161W47.54 £
Jersey HuntKey R90 300W 80+ Dorado90%167W41.74 £

Con­clu­sion: This is the first scen­ario where new high­er-effi­ciency PSU are reas­on­ably price com­pet­it­ive based only on power usage. For such a sys­tem, a high effi­ciency PSU will pay for itself with­in approx­im­ately 3 years. If you plan to keep the sys­tem for more than 3 years a high effi­ciency PSU is a worth­while invest­ment as its TCO will be lower. As energy prices con­tin­ue to rise this TCO advant­age will widen.

Actualizar (25-Dic-2011)

Added the HuntKey Jump­er R90. This PSU changes the con­clu­sion con­clus­ively. It pro­duces sav­ings of over £40, el cual es al menos el precio de la PSU!  Un período de recuperación de 1 año, con la expectativa de que los precios de la electricidad sigan subiendo, vale la pena la inversión.

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