I'm planning to build a new computer that should preferably be very quiet and consume little power. It won't be used for gaming or any other processor intensive tasks except for the very occasional compiling of the kernel of the operating system.
In order to build this system around the Lian Li Q11 case I had the following components in mind:

any Asus or Gigabyte 1155 mini-ATX motherboard,
Intel i3-2100T CPU (using it's integrated GPU),
Noctua NH-L12 CPU cooler with no fan,
Seasonic X-400 Fanless PSU,
two sticks of 2GB DDR3 RAM,
two 3.5" Western Digital Green HDDs,
one Noctua NF-P14 fan placed at the front of the case.

I can't place a fan on the Noctua CPU cooler because of the limitations imposed by the case (it allows a maximum height of 80mm for the CPU cooler including the fan).

With the components and setup mentioned above and considering the size of the case, do you think the computer will be quiet and properly cooled or should I need to change any of the components (maybe using a non-fanless PSU to compensate for the fanless CPU cooler)? Any thoughts on the HDD rack of that case regarding the intended quietness of the build?

Thanks in advance.

I think a regular i3 2100 would work just as well for less money. The TDP ratings are maximums, not necessarily real world. Under full-tilt artificial loading via Prime95 I've never seen my i5 2500 use more than 60w even though it's TDP is 95w.

For the Noctua NH-L12 you should still be able to use the 92mm fan on the underside as it doesn't affect height clearance.

The Noctua NF-P14 is fairly loud at 12v, quiet with the LNA, and very quiet with the ULNA adapter. I'm not sure what speed you would need to cool your system, but I think you could pull it off with the ULNA.

Overall, the system looks like it would run warm, but not hot while being quiet or silent. The Green drives are very quiet and hardly vibrate at all. The biggest factor for noise will be what speed you need to run the 140mm fan at.

It's not even the maximum for the model in question but for the whole range. So there's no way one of the cheaper 65W model will use anywhere near 65W.
And the TDP seems to take into account the GPU load. So you wouldn't get near the maximum power consumption simply by loading the CPU anyway.

I don't see the point of an expensive fanless PSU in such a build.
There are cheaper and/or better PSUs with a fan which doesn't spin at low load. Or cheaper low-power fanless pico-style PSUs which should be suffcient.

You seem to be right about that. I tried loading the CPU with Prime95 (max power consumption) and the GPU with ATITool and according to Core Temp the CPU power usage was around 67-69 watts.

I think the bottom line is that the low voltage T version CPUs are really only useful in applications where you must limit the TDP to a certain point. In most cases (I think the OP falls in this category) the TDP, especially on a something like a dual-core, is a moot point.

I still haven't met a 1155 BIOS which can't underclock. That'll limit your TDP just fine (except perhaps at boot).
But if you were going to underclock to limit TDP, you'd be better off buying a Celeron or something in most cases. That'd limit your draw at boot too. So even if you wanted a T, you probably wouldn't want the 2100T.

I guess once you reach the lowest clock the T versions might have a slight TDP advantage, especially if you can't undervolt. And they're likely to give you slightly more peformance for the same power usage if you don't underclock all the way.
But by all accounts the difference is very slight.

That seems like not much of the CPU cooler if you are are not going to use a fan on it. If this doesn't work out well,

1. Why not consider using a Pico PSU and then using the freed space to put in a large CPU cooler. Any of the large downdraft or tower Noctuas would work. Running fanless I would expect them to perform much better than the NH-L12 running fanless. Running the NH-L12 fanless is asking a lot of such a small cooler.

2. Another alternative is to use this PSU and make room for a larger downdraft cooler... The NH-C14 will fit in with 105mm headroom. It will provide more cooling with no fans... or you can try a 120mm Nexus on the bottom if you want more umph (I would aim the fan upward though to help exit air through the PSU and perhaps keep the PSU's fan from starting up
http://www.newegg.com/Product/Product.a ... 6817104075

3. I would not be so quick to swap out the standard Lian Li fan. They aren't so bad. You should give it a chance to prove itself before tossing it.