0PSU Logoefficacité PSU: vaut la mise à niveau? partie 3

This is the third install­ment in a series of art­icles address­ing PSU effi­ciency. Art­icle one focused on a [int­link id=“76” type=“post”]nouveau serveur théorique[/intlink], art-icle 2 sur un [int­link id=“77” type=“post”]PC de bureau typique[/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 travail).  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 single-core) sur nForce 630i / 7050 mother­board. 2Gb DDR-II35W
2x Sam­sung F4 2Tb HDDs, 7x 1To Vert inc HDDs. WD 1To vert, Seag­ate 1Tb and Sam­sung 1Tb, 1x WD 750 Go 7200rpm entraînement, 1x Max­tor 300Gb 7200rpm drive, 1x WD 200Go 7200rpm disque IDE108W
Areca 1220 RAID Carte5W
2x 120mm Case Fan2W
TOTAL150W

Inintéressant, 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!

le 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. A.C. prélèvement de puissanceSav­ing
ATX v2.2 250W ATX70% (à 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 £
HuntKey Jump­er R90 300W 80+ Gold90%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.

Mettre à jour (25-Dec-2011)

Added the HuntKey Jump­er R90. This PSU changes the con­clu­sion con­clus­ively. It pro­duces sav­ings of over £40, qui est au moins le prix du PSUA pay­back peri­od of 1 an, with an expect­a­tion that elec­tri­city prices will con­tin­ue to rise is well worth the investment.

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