Our load tests utilize a couple of FAST ATE active load testers and a variety of other equipment such as an oscilloscope, power conditioner, temperature probe and a power consumption meter. You can read more about our standard testing approach here.
The tests performed are based around six conceivable setups that are out there and progressively load down the PSU up to the power supply's limits or 1000W, whichever comes first. Since our test equipment's limits are higher than that of the SilverStone ST45SF-G 450W power supply, we can test it to the maximum.
The above tests represent typical loads that we have measured from various systems and are meant to give a rough idea of where your computer might fall in line with our tests. Please keep in mind that each system is different and actual loads can vary greatly even with similar hardware.
Let's start by taking a look at the voltages to see how well this unit did during testing. Starting with the 12V rail, we see 1% regulation from start to finish with a total drop of .09V. The 5V rail managed to stay within 1% of specification with a total drop of .06V from start to finish. Moving towards the 3.3V rail, we see that regulation was within 2% of specification with a total voltage drop of .04V.
DC Output quality for the SilverStone ST45SF-G 450W was good and well within specifications. During Test 1, we saw 21mV of noise on our scope. When we increased the loads in Test 2, the ripple climbed to 33mV at around 3/4 load. During Test 3 under a load of 450W, the oscilloscope showed a maximum of 46mV on noise on the 12V rail.
The SilverStone ST45SF-G 450W is rated for 80 PLUS Gold efficiency. This means that the power supply must perform at 87%/89%/87% efficiency at 20%/50%/100% loads respectively. As you can see, the ST45SF-G 450W passed on our bench, and wasn't close to failing at any point.
The SilverStone ST45SF-G is the first Small Form Factor power supply that we have tested here at TweakTown. It isn't something that we go after simply because most units aren't capable of handling something that our readers would build. The ST45SF-G gives enough power that one could comfortably game on a gaming system featuring something like one Radeon 7970 or GTX 780. If you're only using a single monitor, chances are that you don't need anything more than that, so it will fit the bill just fine.
There are quite a lot of other uses for power supplies like this, such as homemade NAS boxes and small home servers, especially if they aren't running anything but onboard graphics. Let's also not forget that you aren't confined to only utilizing the ST45SF-G inside an SFX chassis. The SFX to ATX adapter sweetens the unit a little bit more, as you can then slip this into a very small case and free up a bit more room.
Performance wise, the ST45SF-G is just what we have come to expect from SilverStone. We'd be quite unhappy if it wasn't up to the standards that they've set for themselves. Voltage regulation faired the best for the ST45SF-G with the 12V and 5V rails staying within 1% of specifications. The 3.3V rail wasn't too far off, staying with 2% itself. DC Output quality could have been a little better, but with a maximum of only 46mV on the 12V rail, it is more than low enough for a stable rig with quality power. The efficiency was spot on during our testing as well, meaning that the ST45SF-G passes with flying colors.
The one drawback to the ST45SF-G from SilverStone seems to be the price. At a shipped price of about $94, you can find much more power, but not in a SFX unit. As with all things that are the best of the best, the price is typically a bit higher. This holds true with the ST45SF-G as you simply won't find a higher wattage SFX unit that performs better with 80 PLUS Gold efficiency and fully modular cables.