I've this server that I built and am planning to use for various tasks (web hosting, building my programs, etc..). Am trying to reduce the noise level a bit as it has gotten quite annoying, and was looking at replacing the crappy PSU that came with the case with a PicoPSU. I did actually look into replacing the fan in the current PSU, but because it's a non-standard size, I haven't actually been able to find one from a place that looked even remotely reputable.

Specs are:
2.6GHz Core i3 2120T (stock clock, and voltages as I don't see a point to fiddling with them)
8GB DDR3 RAM (with the possiblity of a future upgrade to 16GB)
2x 2.5in mechanical hard drives
ASUS P8H61-I motherboard

I'm also looking at replacing one of the spinning hard drives with a 128GB SSD. (possibly either a samsung or crucial one, which ever is the cheapest)

My question is: Will a 120W PicoPSU and 120W adapter be enough to power this machine, at sustained levels of moderate to high load?

Yes, it'll be more than enough... a lot more than enough actually (don't waste your cash if you can get a smaller pico for less and especially if you've got a smaller brick lying around you could reuse).

How much smaller are we talking? The next smallest is 90 something isn't it? I would think that to not be enough.

90W or 80W should be more than enough as well. 60W might be dicey however. Check people's power consumption measurements.
Note that I'm assuming this is going to be a server (no charging batteries or warming coffee from the USB ports).

A picoPSU-90-XLP and a 60W brick would be enough I think. That's what powers my file server.

With many HDDs and a 60W brick that i3 2120T would make sense (the reason for me getting a i3 2100T) but otherwise you might as well go with a non-T part.

A picoPSU-90-XLP and a 80W brick powers my i5 3570K system btw. These CPUs are quite efficient.

If low power consumption is a priority, go with an Intel board instead. They cost a little bit more but they are more efficient than the Asus boards. MSI is cheaper and usually also good, but not quite as good as the Intel boards.

Well the priority was more low noise, than low power consumption.



Yes definitely going to be a server. No charging batteries or coffee warming, but maybe the rare USB flash drive for when the server needs to be repaved.

Also thanks everyone for suggestions. I think I will be looking in to using a 90 watt pico instead of the 120 i was originally looking at.

The 2120T is potentially 35W. Add another potential 25 to 40 watts for the board. See:
http://www.silentpcreview.com/article1200-page5.html

You are up to 75 watts. While the advice others have given you is valid, you indicated is was sound, not power that was your primary concern.

I would use a 120W PicoPSU for a margin of safety. It will likely deliver perhaps 100 watts. That extra capacity will be a handy safety margin in the event you in the event that a run away process inadvertantly loads your computer to 100% over night when you aren't looking.

I would also consider the largest SPCR approved heatsink you can find that will fit easily in your case, and use it with a single 500 rpm Scythe Slipstream. Or a Scythe mugen 2 with it standard PWM slipstream would be cost effective. The fan will never tick past 300 rpm. If you are tight for space, any of the downdraft Noctua, even the smallest, will work just fine as well.

The 80 watt brick may end up delivering 70 watts. The 3570K in theory is capable of absorbing 77 watts all by itself. Isn't that cutting a a bit tight... in the case of an unexpected runaway process... say?

I've actually been doing some experimenting, and found that the stock Intel fan seems to be sufficient in terms of sound and cooling performance when set at the "Quiet" setting in the BIOS. Especially in the cheap case I have that amplifies all the noise. I figure a better case probably would make it even better.

No, the 80W brick can deliver 80W and it's a high quality brick. The TDP of 77W is not reached in any practical scenario.
Besides, right now I underclock a little bit, but that is to get the temperature down a little bit not because of any power concerns.

I guess that depends on if we are talking input watts or output watts. Even the best bricks are going to lose 10% of the input watts by the time the electricity reaches the output.

Isn't this stuff specified in terms of output capacity?