Reccomend an effecient low wattage PSU?

decto · 30 Dec 2007 at 17:34

Hi,

Just piecing together a basic NAS for home storage and looking for an efficient PSU to keep running costs down.

I'm going to use FREENAS, ASUS S939 matx onboard VGA, XP3200, 512MB ram as neither the cheap dedicated NAS drives or an EPIA 533Mhz server seem to be able to provide more than 60Mbps vs 300Mbps+ between PC's on the network. Already have the parts kicking about, Just need a couple more drives.

With a single drive a plug in power monitor shows around 60w so looking at approx £50 per year to feed it. A little more when I add new drives. Currently using a couple of no name PSU's so I though a better brand more efficient PSU may help a little. I need the ATX +12v connector so the little plug in DC-DC EPIA type supplies are no use, quite limited on the +12v output as well.

Any thoughts?

1) Keep the cheapo no name supplies

2) Antec Earthwatts 380

3) ??????

Cheers

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melbourne720 · 30 Dec 2007 at 17:42

Antec are supposed to be good, you should be okay with that.

Amonlym · 30 Dec 2007 at 21:50

take a look at various reviews. start by looking for a "80+ / 80 plus" certifide device. that means it is atleast 80% efficient over its entire output range.

secondly try and avoid a high output psu - they often reach peak efficiency at a much higher load than you will use, a good quality 200w psu would be overkill - maybe theres an 80+ certified shuttle 200w psu?

get RM clock and tweak the power profiles for the cpu. you can very likely wind it down further than cool and quiet will by default, saving a few more watts. - edit, your not using windows - so underclock cpu as much as youc an befor performance drops and undervolt as much as you can and make sure coola nd quiet is on. - an example. my laptop cpu needs 1.5v to run 2200mhz, but runs 2000 @ 1.175. that drops power from 89w to 45w...

set the hdd's to a sensible spindown time, say 10 mins. and make sure spindown is actually working (it doesnt on my motherboard) as this is probably the biggest money saver

try reducing chipset/ram/cpu/ldt/pcie voltages as much as you can and consider swapping thru the ram you have to find the lowest power draw stick you have, then underclock it.

if you have windows installed you dont need a cd/dvd/floppy drive installed any more.

disable all the onboard devices you dont need - soundcard, com ports, lpt port, fire wire, usb, raid controler (if not used)- it may only save .25 watt or so, but thats still a few more pence

dont have any addin cards you dont need - eg an old sound card, while it may just be sitting arround gathering dust dust doesnt cost anything.

consider getting laptop drives or 5200rpm desktop drives as these use MUCH less and noticably less power respectively and you wont notice the difference over network.

theheyes · 30 Dec 2007 at 22:10

Some good advice there. 2.5" drives save a decent few watts. The only reservation I have is buying a new power supply is not going to be cost effective. That Antec PSU for example is £33. There's no way its going to reduce your bill to £17; it may save you a couple of quid at most. It will take a good few years to get you back in the black.

'Think of the environment!' you may say. Yes, you will use less electricity with a more efficient PSU but if you do replace it you're going to have an old one to dispose of. Swings and roundabouts innit.

decto · 31 Dec 2007 at 11:20

Thanks for the suggestions, I'm thinking a new PSU is a good idea as I've no idea how long the no-name units have been in the loft though as there's no dust in them they can't have been used. I have three with the 12v ATX connector but even though the load will be low it will be on 24/7 in the loft so I'd prefer to get an 80 plus or better now rather than have a PSU fail and risk toasting my files.

Some good thoughts there in built in devices, They'll all be disabled, I'll probably try it with one stick if memory for good measure. Unfortunatley the BIOS is typical mATX with no options for clock speed that I could see but I'll have another look. I may be able to do something in the powersaving menu. I'm not sure if FreeNas can use cool and quiet but I'll look into it.

TBH I'm amazed at how little power it uses, an EPIA 5000 on the same psu used 45W and an XP2000 (palamio) uses 120W so 60w for a fully fuctional A64 3200 is pretty good.

Laptop drives would be great if they were a little bigger in capacity. I'm looking to have a pair of 250's in Raid 1 for redundancy, mainly for the music that took days to RIP and family pictures, important files etc so these may be laptop candidates. Then I need at least one big drive to store keepers off the media centre since I'm running out of spaces to put drives.

I read somewhere that some drives can be reprogrammed for different behavious, usually based on noise so I may be able to reprogramme for minimun noise which should reduce heat and energy usage.

Thanks

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