General question about my power needs

[jalisco3k]

Hi all,

I have built many computers in the past, and in all honesty, I never really knew what I was doing power wise =) I mostly just made sure to have "enough" power, probably always having more than I needed.

That said, now, I am in a situation where I want to specifically build a computer that IS power efficient - to save energy =) (but still meet my needs).

I want to build a LOW impact home server to use for the following (and all these things are mostly for learning the technologies - and REALLY low impact), with priority on low power - but still function without interruption. Also, silent or near so, but that is simple with silent or passively cooled items.

1. proxy server - ONLY usable by my inlaws that live in another country, but want to view webpages as if they are from this one. They are not hardcore users, and I mean, NOT at all hardcore. They barely use the computer for web surfing and email checking.

2. email server - basically just for me and my partner - with some pushing involved.

3. cloud server - just for me and my partner, also very light usage.

4. perhaps a file server function, locally, for backups, periodically, not dynamic.

5. and finally, a tor relay - probably the most impactful, but limited bandwidth, so that will be the bottleneck. Not really sure how much computing power this will require.

6. a webserver, with basically just one simple "homepage" and a link here or there to distribute public keys - not much else than a presence =)

Ideally, I just want a dead silent, super power efficient, little computer in the corner of the house.

For almost all of these tasks, my dsl will be used up, which will be the bottleneck. If this is true, then the primary task will be making a low power system that will be stable - and have enough power.

I was thinking about this mobo/cpu combo:
Asus C60M1-I that uses a AMD C-60 dual core processor. I was gonna throw 4GB RAM, a hard drive, and install Ubuntu on it.

My problem now, is solving the minimum power issue.

I have tried to find some "power calculators" even one from ASUS, but can't find one that lists this processor. I assume it's very low power.

There is the whole background and story.

Any help to getting to where I need to go, would be greatly appreciated.

Thanks,
Jalisco

my best estimations, is I will need roughly 100W of power, and per recommendation of having 100W more than you need for a normal system, I would reason probably cut that in half, to need a rounded up total of 150W power supply.

Does that sound about right? Thanks.

Update: Looks like most power supplies are either below 150, mostly under 90W, OR over 300+ Watts. Might just side with the 300 Watts, and then, Just not worry as much about power, and/or throw an extra HDD in it, and use it as a NAS, as well.

Though, to my original question - how does one figure out semi-precisely how much power one needs? I would trust the power calculators, if I found one that had my specific hardware =) but there aren't many. Reading the manual for the previously mentioned motherboard, suggests a 300W or greater PSU.

 

[jaqie]

watts don't mean jack, to put it simply. find out the max amperage of all the devices and get a psu that is larger than that.

If money is less of a concern than noise and output-sizing of a power supply, I strongly recommend getting a picoPSU. Note that the PicoPSU don't even mess with the 12v rail (except in the wide range input ones, that is) so the wattage of the picoPSU is just for the combined 5v, 3.3v, 5vsb rails - meaning you need to size the 12v power brick to suit, and just get the picopsu that can supply the amperages needed on the other rails sufficiently.

I have a couple picoPSU 80 here and I use them routinely on systems with a 95w cpu and video cards that take ~70w. The trick as I said is to make sure the 12v brick is sized properly.

If you want to go the standard psu route, check out the TFX micro ATX FSP power supplies on newegg. I run one of those in my custom-built fileserver, and it's been perfect in every way.

 

[Goros]

Don't forget that PSU efficiency drops as they get hotter and draw more juice. A 500w rated PSU might only safely deliver 400w once it's hot.

They don't rate them at operating temps. They rate them at 50c. Silverstone, Corsair, and a few others rate them under load. You get what you pay for.

 

[ghost03]

Most PSUs are going to be the most efficient operating at some percentage of their maximum output (let's throw out 70% as a guesstimated average), the point being you generally want it sized appropriately for maximum efficiency. Moreover, PSU efficiency is super-duper dependent on the design and quality, as well as operating condition. I always like the 80+ certifications on PSUs that I buy.

As far as predicting power draw, this can get tricky, but my recommendation if you're very concerned with power supply efficiency and sizing, is to grab a kill-a-watt power meter, build the system with another PSU you have lying around, and then get a reading. This will also allow you to try swapping different components and different voltages to minimize your consumption. I've had good success with undervolting and underclocking CPUs for applications like this.