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How many watts for a FreeNAS server w/ 12 5400RPM HDDs?

I know I've asked a similar question before, but I need some clarification.

Here's what I'm building:

FreeNAS server:
AMD Athlon II 210e Regor 2.6ghz (45W TDP)
Asus ATX Mobo (will fill one PCI-e slot with SATA controller eventually)

I want the power capacity for 12 x 3.5 inch HDDs (5400RPM)

No optical drive, no graphics card, nothing fancy (except a handful of case fans including one 220mm fan).

The calculators out on the web provide me with power numbers between 330W and 420W depending on the site.

Honestly those numbers seem really high to me.

Here's the math that I see:
CPU: 45W max
Memory: 15W?? (2 sticks of DDR3 1333mhz ECC memory)
onboard GPU + other mobo activity: 40W? (will be running headless, so probably much lower than this for wattage, right?)
12 x 5400RPM 3.5" hard drives: 84W (12 x 7W peak)
Sata controller card: 40W?

The total for all that only comes up to 224W and I think I am being very conservative in the estimate. Real power draw should probably be much lower.

Do these calculations seem right to you? Where am I going wrong?

Energy efficiency is important since this server will be on 24/7 so I don't want to buy too big of a PSU and waste energy. PSU will probably only be energy efficient up to around 85% or so.

Thanks.
9 answers Last reply Best Answer
More about watts freenas server 5400rpm hdds
  1. I get 244watts recommended 194watts calculated here without a video card at 90% load http://extreme.outervision.com/PSUEngine
  2. Is there anyone who manufacturers a good quality, high efficiency, ATX PSU that is around 200-250W?

    From the searching I've done it really just looks like crap once you drop below the 300W mark.

    Any reccomendations?
  3. Best answer
    300watt Seasonic with 288watts available for +12volt http://www.newegg.com/Product/Product.aspx?Item=N82E16817151086
  4. That's actually the exact PSU I was leaning towards. If they made a 250W model I'd snap it up in a heartbeat.
  5. thenerb said:
    That's actually the exact PSU I was leaning towards. If they made a 250W model I'd snap it up in a heartbeat.

    The cost of making a 300watt or 250watt is almost the same. At least getting a Seasonic you get quality and being 300watts keeps the max load in the 50-75% where it has the best efficiency!
  6. thenerb said:
    That's actually the exact PSU I was leaning towards. If they made a 250W model I'd snap it up in a heartbeat.


    There is no harm in running an oversized PSU, especially by this amount, you WILL NOT use more power, in this case in fact you'd probably use less power at the wall with a 300 vs 250. And it would run cooler, slower fan (also less power) and quieter.
  7. Best answer selected by thenerb.
  8. Awesome. Thanks, guys.
  9. This topic has been closed by Mousemonkey
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