Power Supply Unit
An important component of any SFF PC is a power supply unit (PSU). The thing is that they should not only be small, but should also ensure sufficient power supply. Since the only CPU to fit into Shuttle SN85G4 barebone system is currently selling for $500, we have every right to say that this system is positioned for the Performance segment of the PC market. That is why the PSU should be able to meet the requirements not only of a powerful CPU, but also of a high-end graphics card, and a hard disk drive, which may also turn quite power-hungry.
So, the PSU of Shuttle SN85G4 should be a small and powerful device. Shuttle decided to take a low-profile no-name PSU with 240W capacity and Power Factor Correction (PFC) support (active or passive, they didn’t specify that). I would like to stress that 240W is quite an “adult” power capacity already, because many PSUs in “regular” tower cases offer 250W of power.
The PSU in Shuttle SN85G4 uses not only the primary 20-pin cable and 12V 4-pin cable connected to the mainboard, but also features two 4-pin 12V connectors, two 5V Molex connectors and even a SerialATA power connector. Anyway, you will never be able to use all of them simultaneously. Even if you install all devices that fit inside the SN85G4 case some connectors of the PSU will not be involved. For instance, you will have at least one Molex connector free and a 12V or a SerialATA connector, because two HDDs will never fit into this barebone system.
The PSU is cooled down by a small fan , which also blows warm air outside the system case. The nominal PSU voltage is marked as 100/230V, which means that it automatically adjusts to the input voltage of your place.