These days, everyone is producing power supplies. The market is inundated with cheap power supplies that are unreliable and noisy. The Q Technology Gold Series 350W Power Supply from QuietPC attempts to rise above the low standards and to provide a high quality unit that is reliable and almost inaudible.

Specs

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Mains input voltage: 100V – 240VAC, 47–63Hz Physical dimensions: Standard ATX (86 x 150 x 140 mm) Power conversion efficiency: More than 70% Operating temperature: 0ºC to 50ºC Fan speed control: Thermal, maximum speed limited P4 support: Yes Over voltage protection: +3.3V, +5V, +12V 150% Acoustic noise level: Less than 19 dB (A) Mains input voltage selection: Auto-range Length of motherboard power cable: 50cm (approx) +3.3V maximum output current: 28 A +5V maximum output current: 30 A +12V maximum output current: 18 A Combined maximum output +3.3V / +5V: 220 W Active PFC: Yes Number of Connectors: 2 floppy drive / 5 hard drive / 2 SATA

Initial Impressions

I received the power supply in less than a week after I was notified, and the package came amply protected, and completely undamaged. The box that the power supply came in was simple and informative, telling me which version of the power supply I had purchased (or in this case received) as QuietPC uses the same box for both the 350- and 400-watt models. The box advertises support for serial ATA, an ultra quiet design, active PFC, and support for both Intel Pentium 4 and AMD Athlon systems. Along with the power supply, QuietPC sent a regular power cord in a separate baggie – you’ll see why in a moment. The box had the power supply in all its glory, and a power cord with a different adapter (a European 2-pin plug, as they are sent from Europe). One thing that was lacking from the package were screws to mount the power supply. Since I was replacing an old one, I just ended up using the old screws. But for someone who is building a new system, it may be slightly annoying to buy a power supply and then have to go and find the right screws needed to secure it.

The Power Supply packaging; Open view of packaging

When I pulled out the power supply, I was immediately impressed. Although all of the cords weren’t sleeved, the ATX connector and the serial ATA connectors were, which pleased me. The power supply also looked great. It wasn’t littered with ugly stickers telling you that it’s compatible with your system, and the casing for it was very professional looking. The power supply is a nice metallic color, and has a somewhat reflective surface. This was a nice addition, and was certainly more than what I expected. I also noticed while examining the power supply that it was significantly heavier than my old one. A bad thing? Not at all. As they say, a power supply is worth its weight in gold – you get the point. The back of the power supply is very simple – a mesh grill, and a plug for the power cord. The only fan on the power supply is on the bottom. A 120mm fan provides all the cooling for the power supply. Since it pushes more air (compared to a smaller fan) it can run at slower speeds while still working efficiently, and therefore reducing audible noise.

Power Supply and accesories

Installation

Installing the power supply was a breeze. Minus the fact that there were no screws supplied, I didn’t run into any problems. It fit perfectly into the bracket, and there was ample space between the ends of the power supply and the CD drives. The molex connectors were well spaced over the cables so that the hard drives and floppy drives could be connected using one cable, without having excess wires sticking everywhere. I didn’t need to use all the wires, as I only have 1 floppy, 1 hard drive, and two CD drives, so I hid the extra wires away just to keep my case looking clean.

Case with PSU installed; Close up of installed PSU

Testing

To test the power supply, I used an analog sound level meter while running my system under normal conditions.


System Specs

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Intel Pentium 4 2.4B Processor Intel D845GEBV2 motherboard 512MB PC2700 RAM 80GB Seagate 7200RPM Hard Drive GeForce 4 MX440 64MB Video Card

When I started my computer, I immediately noticed a difference. The computer was significantly quieter, and the only noise that I could discern was from the processor heatsink and the CD drives accessing. A soft whisper is around 20 dB (A). I held the sound meter from about where my head is in the chair, and pointed it towards the computer. The (A) in dB (A) refers to the range of frequencies measured – in this case, (A) only measures frequencies that are audible to the human ear. The sound meter measured slightly above 18 dB (A) with 0% processor load. At 100% load, the power supply got a slight bit noisier according to the sound meter, but I could hardly hear it. The sound meter measured just under 20 dB (A).

Voltage meter used to test voltage; Voltage meter hooked up to PSU to test voltage

I also tested the rails to see how close the voltages were to what they were supposed to be. Using my trusty analog voltmeter, I collected some data:

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+3.3 ::::: 3.25 V (Idle) -- 3.25 V (Load) +5.00 ::: 5.12 V (Idle) -- 5.15 V (Load) +12.00 :: 11.85 V (Idle) -- 11.98 V (Load)

The voltages were very close to what they were supposed to be. Each rail only deviated by less than 3% from the expected values. This was calculated by using the formula (expected-measured)/expected x 100.

Final Thoughts

QuietPC has created a quality product that I would definitely recommend to anyone in the market for a quiet power supply that is still powerful enough to handle most systems. The whole time since I’ve installed the power supply, it has never gotten noisy enough to distract me. One thing to take into consideration when evaluating this product is the capabilities of your system. A powerful system with an inadequate cooling solution will cause the power supply to run the fan at higher speeds, and therefore it will be louder. On the other hand, an adequately cooled system won’t cause the power supply to become louder when the computer is at full load. The only thing that bothered me throughout the whole review was the lack of mounting screws, and that was only a minor annoyance. For those who are looking for to build a quiet system or to replace a noisy power supply, definitely check out the Q Technology Gold Series 350W Power Supply. The Q Tech Gold Series is available through QuietPC for $84.95.