uber PSUs and my electricity bill

MossyUK

MossyUK

MossyUK

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I am looking at doing a DIY nas build and long story short, one of the items on my list is a 650w modular PSU.

Now, the NAS box will also happen to be a VM machine so the spec is souped up from your standard low spec NAS build. It will most likely be a Q6600 from my games machine, whilst I upgrade to something better.

Anyway, I am putting in 5x 1tb WD eco green disks.

I will be turning off two old DIY boxes that currently are my day to day work station and the other VM box.

So in theory, I will be cancelling out some of my power usage - but the 650w PSU is still bigger than the other two combined.

My question is - Does a 650w PSU drain more electricity than a combined ~500w even if its basically doing very little all day long?

I don't mind a small increase, but I don't want to see my cheap skate cost cutting measures actually end up costing me more in the long run.

Any advice appreciated.
 
it will draw as much power as it needs it wont pull 650 watt all day long.

the efficiency rating determins how much power it loses as heat though, most are 80-90% efficient these days meaning for every 100watt only 20%-10% is lost
 
Yep, PC using 100W, PSU will take 120w or so, PC needs 400w? PSU will draw 410W for example.

So just get a PSU that will be the most you'll ever need, running closer to the rated will improve efficiency a bit, not sure how much by for newer PSUs tho.
 
cheers guys - is there a good util out there for doing a quick audit on my current PSU electricity usage?

I would like to see how my new modular gaming PSU compares to the older, cheaper ones in the workstations
 
the 80% effiency rating is only at a certain load, at very low and high load the psu becomes less efficient.
 
5 1tb drivers is going to be a bit of a power drain even if they are green.

Wouldn't it be better to keep a 2 terrabyte drive active and just archive off your old stuff as and when you reach capacity? Possibly use hot swappable drives or something?
 
DIABLO said:
the 80% effiency rating is only at a certain load, at very low and high load the psu becomes less efficient.
Click to expand...

If the PSU is rated 80+ it has to be 80% or better efficient across quite a wide range.

On the whole I believe that most good 80+ PSU's are better than 80% efficient from 10% load to 90% load, and many are in the high 80's in efficiency at around 50% load.

I recently put together an i7 rig with a 650W Corsair PSU, and at idle it was only pulling 79W from the mains, and that was with a GTX275 gpu installed.

As long as you go for a good branded PSU with 80+ rating, then you really are on a winner. That said, I would not buy a 1000W PSU for a computer which was going to be drawing less than 100W on a regular basis, as then you really are hitting the lower limits of the supply and efficiency is likely to suffer.

In my books, if you buy a PSU which is around 25% higher rating than your PC's maximum load, then it should still be in the "comfort" zone when the PC is idle.
 
For what its worth, I wouldnt use a Q6600 in a NAS box if your looking to save power. Its not a power efficient chip. I suppose it depends how much time the machine will spend as a VM, and if your VM server decently supports (or needs) the quad for your application.

Of course, sometimes power efficiency can be taken to far, for example replacing the CPU/Motherboard to save a few watts, is not really money efficient with the purchase price of the equipment. Its not even "green" and carbon footprint saving, when you consider the energy used to make the processor in the firstplace... So giving it a good long life is green and environmentally sound :)
 
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