Performance, Performance Per Dollar, Noise And Efficiency Ratings
The following graph shows the SX550's total performance, comparing it to other units we have tested. To be more specific, the tested unit is shown as 100 percent, and every other unit's performance is shown relative to it.
The SX550's relative performance score puts it way behind the SF450 and SF600. However, thanks to decent ripple suppression, it manages to surpass the SX600-G, which appears higher up in SilverStone's portfolio.
Performance Per Dollar
The following chart may be the most interesting to many of you because it depicts the unit's performance-per-dollar score. We looked up the current price of each PSU on popular online shops and used those prices and all relative performance numbers to calculate the index. If the specific unit wasn't available in the United States, we searched for it in popular European Union shops, converting the listed price to USD (without VAT). Note that all of the numbers in the following graph are normalized by the rated power of each PSU.
The SX550 easily beats SilverStone's other SFX-based units thanks to its fair price. However Corsair's SFX solutions are tough opponents, despite higher prices, due to superior performance.
The graph below depicts the cooling fan's average noise over the PSU's operating range, with an ambient temperature between 28 °C and 30 °C (82 °F to 86 °F).
The SX550 isn't as quiet as the SF450 or SX500-LG. However, it is quieter than the SX600-G. As for the SF600, we still haven't tested the second sample that Corsair sent a while ago to check if our first unit had a problem with its fan control circuit. According to Corsair, the SF600 should be as quiet as the SF450.
The following graph shows the PSU's average efficiency throughout its operating range with an ambient temperature between 28 °C and 30 °C.
This graph clearly shows the SX550's low efficiency compared to other Gold-rated units. The ACRF topology that this PSU uses cannot meet the efficiency levels of other topologies utilizing LLC resonant converters.