Cooler Master RS-150-FSGA-J3 Power Supply (150W)
The first system case discussed in this review comes with a 150W power supply which is a very low wattage rating by today’s standards. But considering the limited capabilities of the mini-ITX platform (and this particular system case does not permit to install expansion cards altogether), this should be enough to power up a quad-core CPU even.
It goes without saying that power supplies in such system cases are mostly non-ATX. There are over half a dozen standardized form-factors of compact power supplies and some manufacturers even order absolutely nonstandard PSUs for their products. We can understand the manufacturer who finds it hard to fit a PSU into the dimensions of a super-compact computer enclosure, but this variegation means that it is next to impossible to find a replacement power supply if the default one fails.
By the way, many mini-ITX cases come with external power supplies of the notebook variety with an output voltage of 12V, the rest of the necessary voltages being produced by a small switching DC-DC converter card located inside the case. There are no such models in this review, though.
So, the Cooler Master RS-150-FSGA-J3 has a narrow and long case with a small cooling fan at one butt-end.
The PSU can yield up to 120W out of its full wattage of 150W via the +12V rail. The specified compliance with the ATX12V 2.2 standard should not be taken seriously as this standard does not describe such wattages and dimensions. The author of the label must have decided to use what abbreviations would be most familiar to the end-user.
The real maker of this PSU is FSP Group.
Despite the small size, the component density is not higher than in modern full-size products (considering that the latter have much higher wattage). This is due to the modest heatsinks on the power elements which are aluminum plates without any ribbing. You will see shortly how effective they are in terms of cooling.
The PSU has an active PFC device and supports a full input voltage range from 100 to 240V. It has joint voltage regulation and the following cables and connectors:
- A mainboard cable with a 20+4-pin connector (36cm long)
- A CPU cable with a 4-pin connector (36cm long)
- One cable with two SATA power plugs (19+14cm)
- One cable with two Molex connectors and one floppy-drive plug (19+19+16cm)
The floppy-drive plug seems unnecessary at first. However, it can be used for a DVD drive with PATA interface. Power adapters for such drives are connected to a floppy-drive power connector.
The output voltages are stable enough. They violate the required limits only at a strong misbalance towards the +5V and +3.3V tails which can hardly occur in today’s computers. The PSU yields its full specified power without problems.
The high-frequency voltage ripple is very low and far within the required limits.
The PSU is 83-85% efficient but its efficiency plummets under low loads although such loads are typical of configurations that are likely to be assembled in super-slim system cases (if not an Atom, it is going to be a Celeron E3xxx or Pentium Dual-Core E5xxx processor).
As mentioned above, the PSU is cooled with a 40x40x15mm fan from Yate Loon.
The fan speed is adjusted depending on the temperature sensor located on one of the heatsinks. The sensor does not sit tight and can easily move back and forth, so the adjustment may vary depending on the specific PSU sample.
Here, the fan starts out at 4650rpm. It increases its speed slowly up to a load of 100W and then accelerates more quickly.
Unfortunately, the fan (and, consequently, the whole system case) is not good acoustically. It produces a distinct whistling sound which is far more irritating than any hiss of air. Under low loads the whistling is soft enough for an office, but you may not like it at home.
If you are not afraid of losing your power supply warranty and doing some manual work, you can replace the default fan with a slower, quieter and rather powerful (thanks to a thicker frame) Scythe Mini Kaze Ultra SY124020L.
The fan has to be installed outside the power supply, but the system case allows doing that easily. After this modification, the power supply becomes much quieter and the whistling disappears completely. However, this method of solving the noise problem won’t suit all consumers.
The standby source is rated for a current up to 2A and copes easily with its job.
While we don’t have any complaints as to the electrical parameters of this power supply, its noise (the spectrum of the noise, to be specific) makes it unsuitable for home. The problem can be solved by replacing the default fan with a quieter one, but it is sad that the manufacturer has not done this modification back at the factory.