PSU sizing for home file server

[monarchdodra]

After testing and liking freenas 8, I decided to get dedicated hardware for it. My Phenom 9950 is just too big of a power hog...

My goal is just having a humble home file server.

The case if the huge Antec P180. It will house:
4x 7200 3.5" HDDs
2x 5400 2.5" HDDs
2x8 Gb DDR3

I wanted a low power cpu, either an Intel Atom, or an AMD E-series. Preferably dual core. I wanted one of these mobos:
Asus E35M1-l. E350. Passive, 6xSata.
Asus AT5NM10TI-l. D525. Passive, 4xSata.

The Atom draws a bit less power, but has less sata. Atom mobos with 6x sata are really expensize. Not sure which to go for... :/

The BIG question is the PSU... I'm having a lot of trouble finding out what to go for!
-Pure Power L7 300W. An overall pretty good PSU. 80+ Bronze. Has enough connectors, without going into PCI express
-FSP180-50LE. A much lower PSU. Not sure how noisy... (important).

I think my system will draw 40-60 W, making 300W over rated, but I'm not sure about the FSP 180...

What are your thoughts on the build?

 

[Trianian]

Keep in mind that each HD will require about 2 amps to start it spinning.

If you only need 60 watts when the system is running, a good quality 300 watt PSU shouldn't draw much more power than that 150 watt. Modern, high quality PSUs can be quite good at only using the power that is requested.

There are sites on the net that perform detailed analysis of PSUs. Generally, the more you pay, the greater efficiency you'll get.

 

[ProtoSD]

P = I x E

That would mean that 2 amps x 12v = ~24w

2 amps is a little high

My mini ITX system has a 150w PICO power supply with 5 disks, it peaks at 60w during a scrub and has been working fine for ~1.5 years.

With AHCI enabled you are supposed to be able to stagger the spin up of your drives automatically, though I've noticed on mine that only happens during a reboot.

I think people tend to WAY over rate the wattage required by their power supplies. (And yes Mark, I know you think mine is too small....)

Yes, a shitty power supply can cause all kinds of funky weird and hard to diagnose problems if it's too small or going bad.

If you get a good quality power supply, it doesn't need to be "over the top".

If you're powering it off & on all the time, that will put stress on it, just like the other components of your system.

Mine is on continously, it's kept on a UPS, and idles under ~40w.

 

[survive]

Hi monarchdodra,

I'm a big believer in paying for a quality power supply. If I were you I would look for something like a Corsair, Antec or Seasonic. No matter what look for something sporting at least an 80+ Bronze rating.

It's going to be tough to find something with good quality that's small enough for your system. When you narrow down your choices compare them with the ratings listed here:

http://www.plugloadsolutions.com/80PlusPowerSupplies.aspx

If you click on a brand name you will see the 20%, 50% & 100% efficiency ratings for the various models that have been tested. Look for something that's got good efficiency at between 20 & 50% since that's where you are going to be running most of the time.

-Will

 

[monarchdodra]

Thanks for your replies.

The link is really really useful.

My current board spins the drives up sequentially, so there won't be any huge "everything spins up at once spike". I can only hope my new board will support AHCI and do the same.

I found a couple 300W 80+ Bronze PSU, but i can't find anything less that is at least 80+. For gold or silver, you have to go up to 400W :/ (on my market).

My box will probably spend 95% of its time idling, with the discs spinned down. At about 40W (?) My PSU can be all the gold it wants, if I'm drawing only 10% of its rating, who knows what the efficiency is?

----
I'm wondering about pico PSUs... Are they efficient? I was thinking about a 150W pico PSU. I'd have to combine it with one of these right? They come with like NO connectors whatsoever, which doesn't look convenient at all! Am I just supposed by plug Y connectors to Y connectors to Y connectors?

One of the advantages of these pico PSUs over smaller flex-atx type psu is that they are passive. I'm really cautious about the noise generated by the 150W-220W PSU with 4cm fans.

 

[ProtoSD]

I'm wondering about pico PSUs... Are they efficient? I was thinking about a 150W pico PSU. I'd have to combine it with one of these right? They come with like NO connectors whatsoever, which doesn't look convenient at all! Am I just supposed by plug Y connectors to Y connectors to Y connectors?

One of the advantages of these pico PSUs over smaller flex-atx type psu is that they are passive. I'm really cautious about the noise generated by the 150W-220W PSU with 4cm fans.

It's been awhile, but somewhere I read they were something like 96% efficient. Yes, you need one of the AC adapter "power bricks", unless you want to run it off of a solar panel with a couple of 12v solar/car batteries ;) which it can do quite well.

The other thing is, since it's sooo tiny, it opens up a lot of extra space in your case, keeping it cooler.

Yes, they only come with one power connector, and there's a second one on the board to plugin an extension with more.
I custom built/soldered my own power cable, so its just one perfect length cable with the correct number of connectors. You can probably order something rather than do Y to Y to Y etc.

I found this quick link on efficiency, it's a forum discussion: http://www.silentpcreview.com/forums/viewtopic.php?t=56048

You can also google for "pico power supply efficiency".

I think they have a 200w version now also (http://www.mini-itx.com/store/psu). There are a couple or so manufacturers.

EDIT: They do have a 200w version, but it's out of stock. Here a link to their full selection:

http://www.mini-box.com/DC-DC

 

[monarchdodra]

Hum... so many possibilities! Thanks for the links!

I think the 96% is a false figure, because it is the efficiency of the DC-DC conversion, but it does not take into accout the power lost in the brrick. Last I heard, those things were something like 70% :/

Overall, PICO PSU seems more expensive...

I need to sleep on it.

 

[RichR]

Just because a PSU is rated for 350W doesn't mean it's using 350W - so by going for a PSU that is more efficient at 50% (or within a range there abouts), you'll actually end up saving money.

Even though protosd knows a lot more than me in most of the FreeNAS stuff, I have to totally disagree with him on his statement "2 amps is a little high." To make a possibly really long story short, the math is the math, and frankly forget about the total wattage of hard drives at startup because it's not comparing apples to apples in extreme cases (like mine), so you're better off learning and doing the true math in the first place.

His formula is correct, but the application is incorrect. If we were working on a house (in the US) and based everything on 110V we'd be fine. However drives, and especially SATA, use at most 3 voltages: +3V, +5V, +12V.

throw 3V out the window. Even though it's in the spec, I don't know if anyone at all uses the 3V rail.

Where the math comes in is in both the 5V and 12V rails. Look at your PSU - and again , I'm using an extreme case. Do the math for all your components and you'll see that the 12V rail is the most needed, followed by 5V, then 3V.

Your PSU has ratings for each rail. Look at the specs of your hard drive. For example, a Hitachi Desktar 5K3000 (a popular HDD) uses (at spin up) 1.2A @ 5V, 2.0A @ 12V.

10 drive example.. you would use 12A @ 5V and 20A @ 12V (on startup only, which unless you have staggered spin up is where you'll use most of the power [green drives are another story])

For a large enclosure with lots of HDDs, that will be the biggest power drain. For a gamer, the power get used by the processor and the higher end video cards. My point is, depending on the rating of your PSU, and the 5V rail is almost always smaller than the 12V rail, the math will work.

I have 45 Hitachi drives, 2 medium PSUs rigged together to start together, and have no power issues. If you get a very high quality PSU that meet's your current (sorry for the pun) and future power needs, it's probably efficient enough at around 50% that you'll love it.

Finally, when you get into enclosures with many hard drives, your problem finding a PSU won't be with the 12V rail, but the 5V rail.

just my $02.

Rich

 

[monarchdodra]

FYI: I ended up buying a PICOPSU:
I bought the picoPSU-160-XT: http://www.mini-box.com/picoPSU-160-XT
Along with a 150W bloc.

I chose the 160-XT because it was one of the only models out there with a 24-pin ATX connector (others are actually 20-pin only). The other model is the 150-XT, sold for the same cost. That and the manufacturer says the 150-XT is deprecated, and replaced by the 160-XT... The actual efficiency for these things is about 97% apparently, so bigger is better.

In terms power draw (from the wall) my system draws 24W during idle w/ spindown, about 60W during idle with 4 drives spinning (7200 RPM). The system can draw up to 80 what during load, though I did not try any PSU stress testing. The system draws a 110W peak for about 5 seconds during boot. I think 150W is perfectly sized. A 120W brick may have provided a slightly better efficiency ratio given the draw, but there would not have been a lot of overhead left. If I ever add more drives, or decide to get a bigger CPU, I'll need a dozen or more watts.

The actual bloc is just plain silent. Combined with a passive board, the system makes 0 noise when the drives are not spinning. The BEST part of the pico-PSU is that the actual power cables are about 15 cm long, thin and soft, and originate from the ATX-plug. This keeps the cables inside the box to a strict minimum. I put the actual bloc inside the case (It is an full sized ATX case), inside the old spot reserved for the PSU.

Overall, I am VERY satisfied by the system. The PSU combo cost me about 110€, whereas a bronze-gold 350W would have cost me about 50-70 €. IMO: The silence + convenience + the fun make the PICOPsu worth it.

 

[budmannxx]

FYI: I ended up buying a PICOPSU:
I bought the picoPSU-160-XT: http://www.mini-box.com/picoPSU-160-XT
Along with a 150W bloc.

@monarchdodra: that looks like a pretty great solution. What did you do to get the 6 SATA power connectors for all your drives? Did you go with a bunch of Y-splitters or something more elegant?

If we were working on a house (in the US) and based everything on 110V we'd be fine. However drives, and especially SATA, use at most 3 voltages: +3V, +5V, +12V.

throw 3V out the window. Even though it's in the spec, I don't know if anyone at all uses the 3V rail.

@RichR: the Pico PSU monarchdodra linked to says it puts all its power out on the 12V rail. As you mentioned HDDs list specs for both the 5V and 12V rails. Do they need power on both to work properly? Or is it OK to just have the 12V?

 

[RichR]

@monarchdodra: that looks like a pretty great solution. What did you do to get the 6 SATA power connectors for all your drives? Did you go with a bunch of Y-splitters or something more elegant?


@RichR: the Pico PSU monarchdodra linked to says it puts all its power out on the 12V rail. As you mentioned HDDs list specs for both the 5V and 12V rails. Do they need power on both to work properly? Or is it OK to just have the 12V?

Not to be a smart ass, that's not what the manual says....it's **input** is 12V, the outputs are listed in the manual, which includes 5V, 3.3V, -12V and 12V. To actually answer your question, yes, standard hard drives (most) require 5V as well as 12V. Additionally, the SATA specification also lists the 3.3V as well, although many drive manufacturers don't use it anymore. (it's the orange wire you see on the SATA power connector). Some connectors only utilize 4 leads - in that case, those manufacturers have done away with the 3.3V lead.

 

[budmannxx]

Much appreciated. I misinterpreted the "Operates at only 12V" from the product page to mean it only output 12V.

 

[monarchdodra]

@monarchdodra: that looks like a pretty great solution. What did you do to get the 6 SATA power connectors for all your drives? Did you go with a bunch of Y-splitters or something more elegant?

Well the PICOPSU actually comes with 2x (1x SATA + 1x MOLEX) connector (technically, it is sold with 1, the second being optional). From there, fitting both molexes with a (1x molex -> 2x SATA) will give you a total of 6x SATA. The fact that the cables split at the end, rather than at the root, actually keeps the box tidy.

@RichR: the Pico PSU monarchdodra linked to says it puts all its power out on the 12V rail. As you mentioned HDDs list specs for both the 5V and 12V rails. Do they need power on both to work properly? Or is it OK to just have the 12V?

The "Power Bloc" sends out straight up 12V to the PicoPSU. The PicoPSU then forwards that 12V (maybe cleans it a bit), as well as converts some to 3.3V and 5V. So you have all the voltages you need. I'm not sure how much it can convert for each voltage, but probably enough.

The most costly component is the "Bloc" anyways, and there are vendors that sell "150W Bloc + 192W Converter" combos. The converter isn't costly, so if you buy that, you are 100% safe... But quite frankly, I wouldn't worry about it.

 

[mtrawczy]

The web site you link to is FANTASTIC It is going in my tech links folder a big thanks

Hi monarchdodra,

I'm a big believer in paying for a quality power supply. If I were you I would look for something like a Corsair, Antec or Seasonic. No matter what look for something sporting at least an 80+ Bronze rating.

It's going to be tough to find something with good quality that's small enough for your system. When you narrow down your choices compare them with the ratings listed here:

http://www.plugloadsolutions.com/80PlusPowerSupplies.aspx

If you click on a brand name you will see the 20%, 50% & 100% efficiency ratings for the various models that have been tested. Look for something that's got good efficiency at between 20 & 50% since that's where you are going to be running most of the time.

-Will