Introduction & Packaging
Compact systems are becoming increasingly popular, with many chassis now being so small, that they no longer support the common ATX PSU standard. This is where smaller form factor power supplies, such as the Chieftec SFX 500GD-C we have on the test bench today, come into play. The smaller form factor makes them perfect for compact system builds and with 500W of power on offer, this tiny PSU still has more than enough juice to power a decent gaming system, making it a prime choice for those building a small LAN gaming system, HTPC style gaming system, or even just those who have limited room for a desktop rig/workstation.
In terms of hardware, the GD-C ticks all the right boxes, with a powerful 40A +12V rail, modular cables for easy installation and cable management, 80 Plus Gold efficiency and all the safety features we have come to expect from a modern unit. Of course, the real big, or should I say little, feature is that it’s all housed in a tiny little unit.
Packaging & Accessories
The box is nothing too fancy, but it does have a nice image of the PSU on the front, which shows off the modular cable design.
There’s very little in the box, so little that you’ll only find a user manual beside the PSU and modular cables. Annoyingly, there wasn’t even an AC mains cable. Fortunately, we have a few of those lying around, so that’s no going to cause issues with our testing.
A Closer Look – Exterior
Power Supply Unit
The unit features a 120mm fan, which is pretty good as many small SFX units feature the smaller 80mm fans, so this bodes well for the cooling of the unit and lower fan RPM under load, we hope. However, this does mean the unit is 125 long, where most SFX units are a more compact 100mm, although this shouldn’t cause many issue with most builds, it’s worth keeping in mind.
On the base, we’ve got the main specification sticker, as you can see we’ve got powerful amps on the rails, especially on the +12V rail, where we’ll likely be putting the most load, such as with a high-end graphics card.
Everything is neat and tidy here, with a range of connectors and a sticker which details each one. We’ve got the 24-pin motherboard connector, an 8-pin CPU, two 6-pin peripheral connectors and single 8-pin for the PCI-E.
The side is fairly standard, with a tidy looking branding sticker.
A few serial numbers and QC stickers on the other side, nothing fancy, but then again, it doesn’t need to be.
Lots of ventilation around the back, always a good sign. There’s also the master powers switching for when you need to fully power off your system.
The included cables are of a good quality, although they do look a little basic. There’s a 24-pin, 2 x SATA/Molex, 8-pin to dual 6+2-pin, and a 4+4-pin for the CPU.
A Closer Look – Interior
There’s quite a lot going on inside this unit, no surprise given that all that hardware has to be compressed into the limited amount of space of an SFX form factor. Surprisingly, everything is quite neat and tidy though, with a good amount of airflow through the central section of the unit, which should help cool all the major components. The unit was manufactured by Sirfa OEM for Chieftec.
There’s a single bulk capacitor, which is rated for 400v, 390uF at 85c.
The AC line in and filtering stage looks pretty robust and while some of the soldering looks a little scruffy, it’s certainly secure.
There’s a mixture of good quality Japanese caps for the rest of the outputs, they’re a little buried under some of the rear panel cables, so it’s quite tricky to show them. Perhaps these cables on the interior could have been shorter, but it shouldn’t cause any major issues. All of the capacitors are a mixture of Taiwanese Teapo and a few Nippon Chemicon thrown in for good measure.
A smaller vertical PCB here is used for controlling the PFC and voltage regulation.
Two large passive heat sinks run through the PSU, which should help greatly with the overall cooling of vital hardware.
The fan is a Globe Fan 120x15mm design, which is capable of up to 1800RPM, although I doubt it’ll ever need to reach those speeds to cool this unit.
At eTeknix we take the power supply testing procedure very seriously and have invested a lot of resources into acquiring the appropriate testing equipment. For all power supply reviews we test the power supplies with dedicated power supply testing equipment. This means we are able to get the most accurate results from our testing as opposed to using software benchmarks (such as OCCT) or multi-meter readouts which are broadly inaccurate.
Our test machinery is as follows:
- Sunmoon SM-5500ATE Active Load Tester (1200W rated)
- Stingray DS1M12 USB Oscilloscope
- Voltcraft DT-10L laser tachometer
The eTeknix test procedure involves:
- Testing each power supply at 20/40/60/80/100% load (with balanced load across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power “pulled at the wall”) and voltage regulation (deviance from expected voltages of 3.3/5/12 on the main rails).
- Measuring ripple with an oscilloscope at 20/40/60/80/100% load.
- Measuring fan speed after a stabilisation period of five minutes at each load scenario using the Voltcraft DT-10L laser tachometer and a reflective strip on the fan.
- Testing each power supply’s OPP (Over Power Protection) mechanism and seeing how many watts each power supply can deliver before shutting down
Other things to consider are that
- We recognise that a single yellow 12 volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) and so we used an adequate number of cables for each power supply to ensure there is not efficiency loss from poor cables selection
- Our Sunmoon SM-5500ATE power supply tester is not capable of testing more than 300W on each of the 12 volt rails so where a power supply provides more than 300W on a 12 volt rail that power is distributed over multiple 12 volt rails on the load tester. For example a power supply with one 12 volt rail supplying 750 watts would be spread equally over three 12 volt rails on the load tester, a power supply with two 450W 12v rails would be spread over four 12v rails on the load tester, two 225W 12v rails for each of the 12v rails on the unit.
- We use the same time scale and horizontal millivolt scale on our oscilloscope for all ripple tests, that is a 20ms T/DIV (horizontal) and a 0.02 V/DIV (vertical) meaning the scale is from -80mV to +80mV, ATX spec dictates that the 12v rail must fall within 150mv of ripple and the 3.3/5 within 50mv so that scale allows us to include both 150 and 50mV peaks. (Some older PSU reviews use different scales which were later ditched as the visual representation they give is inadequate, in these reviews written measurements are provided only).
- Deviance is the terminology used to represent the way voltages diverge from the expected values
Efficiency, PFC and Voltage Regulation
To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage.
Overall these results are very good, I was actually expecting there to be a little more deviance across the loads, but the unit kept things running pretty tight and should provide you will stable power.
Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies.
Efficiency was superb, running at the upper end of the 80 Plus Gold standards, which should help save you a little more on your electricity bill in the long run.
Power Factor Correction
Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source – Wikipedia).
PFC performance was exceptionally good, put performing most other PSUs on the market, even when compared to full-size ATX units!
Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs. millivolt ripple is measured by the peak to peak size of the voltage curve.
The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications. Millivolt figures are stated to the closest increment of 5 given their variability.
|Load (%)||3.3V Ripple||5V Ripple||12V Ripple|
Ripple was pretty good across the board. Sure, it’s a little high at 12v at 100% load, but it’s still within a safe margin and about where I expected it to be for a compact unit such as this.
3.3 volt @ 100%
5 volt @ 100%
12 volt @ 100%
Over Power Protection and Max Wattage
Power supplies often quote as having various protection mechanisms such and the most important of these is Over Power Protection. In our testing we crank up the power draw until the power supply either shuts down (meaning the OPP mechanism is present and working) or blows up (meaning it is either not present or not working). We then note the maximum power consumption before the power supply shut down (or blew up).
OPP performance was ok, giving 16% more power before the unit cut out. This is ok if you get a small power spike from time to time while gaming, but the PSU won’t let you push it very far for long.
When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Sunmoon test equipment and air conditioning corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. The ambient temperature during testing held constant at 22 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario.
In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used.
- Below 800 RPM – Inaudible/Silent
- 800 to 1000 RPM – Barely audible
- 1000 – 1200 RPM – Audible but still quiet
- 1200 – 1400 RPM – Moderately noisy
- 1400 – 1800 RPM – Noisy
- 1800 RPM or higher – Intolerable
The fan speed was nice and low right up until it hit 100% load, where the fan kicked up to a still fairly mild 860RPM. While it may look ilke a big spike, it was still very quiet and barely audible.
This may only be a 500W unit, but due to the compact size and the 80 Plus Gold levels of efficiency, you can expect to pay a premium vs normal ATX units. The Chieftec SFX-500GD-C SFX-L Power supply will set you back around £80 from most major retailers, although it can be a little tricky to find stock, so you may need to shop around.
I’m pretty impressed with this unit, sure it’s nothing groundbreaking, but it’s certainly ticking all the right boxes for those seeking a powerful and compact power supply. Of course, I use the word compact with a pinch of salt, as this is an SFX-L power supply, which is a nice was of saying it’s a large version of a small power supply. Make of that what you will, but it’s still a heck of a lot smaller than ATX units and it’s going to fit into a wide range of compact chassis designs with ease.
Its design is a little boring in some regards, especially with the multicolored and thinly braided cables. They’re not bad, they’re just a little unattractive, so may not be a first choice for those with a chassis that features a window panel. Then there’s the issue with the AC power cable not being included in the box, that’s a bit of an odd one, as you do need to plug this in for it to work, although it’s a problem that is easily resolved as those cables are very cheap to obtain and most people have a spare one lying around somewhere.
The performance was great, with good voltage regulation, good efficiency, and a reasonable ripple. Sure it could be better, but then you would expect to be paying more for such a privilege. Compared to their rivals, such as the Silverstone SX600-G, this isn’t the most powerful in its class, nor the smallest, but it does offer a good amount of power, efficiency and features for a fairly reasonable cost, which is about as much as you could hope for.
- Good voltage regulation
- Modular cables
- Powerful 12v rail
- Quiet fan
- Good efficiency
- Competitive price
- Limited availability
- Bland cables
- AC cable not included in box
“Building a compact system that can still run a high-end graphics card and CPU combo is becoming a much easier task and the latest effort from Chieftec would make a great start to and SFF gaming rig or workstation.”
Thank you Chieftec for providing this review sample.