The picoPSU - a HTPC builder's best friend
I recently bought the AYWUN A1-8989 case for my new mini-ITX HTPC build. I chose this case primarily because it supports a full size 3.5" internal hard drive and a full size 5.25" internal optical drive, which means I can stick in cheap parts rather than having to fork out crazy prices for a slim-drive blueray, etc. The case also comes with an internal 150W PSU and only costs $89 (AU), which is very cheap compared with some of the big-name alternatives.
The case is actually quite good: small enough to place next to a PS3 under the TV, stylish enough to impress and roomy enough to fit in a mini-ITX board with a standard-sized cooler, full-size PCI-e card and the full-size drives. The PSU however is somewhat loud. No louder than a standard ATX power-supply, but a little disappointing for a HTPC build where silent operation is desirable.
I started looking for some alternative silent PSUs I could install in this case, but finding one that fit was proving difficult. The PSU is a Comstars KT-T150FX and measures 130x65x65. The name implies it's a TFX form-factor, but the sizes for these seem to vary. I wasn't able to find any other PSU that fit these dimensions exactly, let alone a silent one...
I did however come across this little gem, the so-called picoPSU. You really need to follow that link to see this thing, but basically it's a 20pin ATX connector with a tiny little board on top, 12V rail cable, 2 standard internal power connectors, and that's it! This thing is absolutely tiny and should fit in pretty much any case. It's peak power output is rated at 120W, which should be enough for most low power HTPC builds (wouldn't use it for a desktop PC with a high-power CPU and GPU).
How can they make it so small? Well...it's cheating really...as it's a DC PSU. That is, it has an additional cable with a standard DC connector that takes 12V as input. So instead of plugging it directly into a power-point, you need an external laptop style adaptor that does the AC-to-DC conversion (which generates all the heat and takes all the size). So it's basically breaking up a standard ATX PSU into two sub-components, the converter, and the ATX adaptor...
Regardless, it's still a really neat product and mine's currently on order from mini-box (Australia/Perth based, ship to Sydney for $14). Note that they have a few different models ranging from 60W to 150W (good luck finding a 150W DC Adaptor though, their best adapter on the site is listed as 102W and has it's own internal fan).