Compact Dimensions Plus Silent Operation
The 30mm increased depth of the SX500-LG compared with the SX600-G that we reviewed previously accommodates a larger fan, which results in a PSU with silent operation even under full load conditions. On top of that, the SX500-LG achieved better overall performance than its higher-wattage SFX sibling and currently costs $20 less, making it a no-brainer for those who need a PSU with compact dimensions. The 100W difference between the two models is insignificant, since both models come armed with two PCIe connectors, meaning that they only support one high-end graphics card. If the higher-wattage SX600-G came with four PCIe connectors, then we could justify recommending it over this 500W model. However, given the current situation, if your chassis has enough room for the SX500-LG, then you should consider it over the SX600-G.
SilverStone's decision to include a product that bridges the gap between SFX and ATX PSUs was a wise one. The 80mm fans imposed on the SFX form factor are not only noisy under higher speeds, but they also emit a high-pitch tone that can quickly become grating. On the contrary, the 120mm fans used in the SFX-L units can efficiently cool down mid-capacity PSUs without the need for increased RPMs. Besides that, they don't suffer from the high-pitch noise problem. Sirfa/High Power delivered a good platform for SilverStone, although we believe it could offer better ripple suppression on the minor rails. There was enough space available to add some extra filtering capacitors on the modular board, though this would increase production costs, especially since only Japanese capacitors are used. Also, although a branded bulk cap was used in the APFC converter, we would like to see it rated at 105 °C instead of 85 °C. Surely what matters most is the quality of capacitors in the secondary side since they aren't cooled as well in most cases and more stress is applied to them. Nonetheless, the quality of the bulk caps plays a significant role and this is why most manufacturers usually use high-quality caps in the APFC converter with 105 °C rating.
The SX500-LG is a good PSU and is among the very few belonging to the custom SFX-L form factor. With its recent implementations, which include digital PSUs, Sirfa has proved it has the required know-how and proper facilities to build good products. And we believe that with a little more tuning this platform can be further improved. If you are looking for a compact, mid-capacity PSU with very low noise output, then the SX500-LG should be on your short list.
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Aris Mpitziopoulos is a Contributing Editor for Tom's Hardware, covering Power Supplies. Follow him on Twitter, Facebook and Google+.
As for higher wattage fanless ATX units, only with Titanium efficiency (for less energy dissipation)