SilverStone SX550 SFX PSU Review

SilverStone continues to enrich its SFX PSU portfolio. One of the most recent additions is the SX550, a budget-oriented unit featuring Gold-class efficiency and fixed cables instead of modular ones. As you can tell, it's intended to bring prices down.

The problem with SFX power supplies is that they're expensive. In the tech world, the smaller a component is, the more it usually costs. SilverStone seems to understand this, and the company now has a budget-friendly SFX that is made more affordable with fixed cables, shedding the modular leads many enthusiasts favor. Native cables might be a good solution for lowering a PSU's price without affecting its performance, but they also make the installation process much harder. In addition, unused cables can negatively affect airflow, particularly in a compact chassis. Fortunately, you'll probably come close to using all of the cables SilverStone attaches to its SX550.

This new model offers plenty of capacity for its compact dimensions; the single +12V rail can deliver up to 45 A of current. Considering its 80 PLUS Gold certification and ability to deliver full power at up to 50 ℃ ambient, SilverStone's latest looks promising. Thanks to its capacity and pair of PCIe connectors, the SX550 can support a gaming machine equipped with Nvidia's GeForce GTX 1070 or 1080. SilverStone is also promising quiet operation, despite the use of an 80 mm fan. Competitors like Corsair use larger fans in their SFX offerings to lower noise output. However, the combination of high efficiency and an optimized fan profile can also do the trick under normal operating conditions.

But the SX550's strongest asset is its price tag, which at time of review is $95. Corsair's SF600 is this unit's most notable competition, and that model sells for $120. Though the price difference between them is significant, SilverStone's SX550 needs to perform well if it wants to usurp the class-leading SF600.

Specifications

This is a budget-friendly unit that SilverStone says was primarily designed for system integrators looking for value. In other words, don't expect extras like modular cables or a large 92 mm fan. On the other hand, all basic protection features except under-voltage and over-current (for the +12V rail) are included. Because the SX550 only has one +12 V rail, there is no need for OCP.

According to the SFX12V v.3.3 guidelines, the SX550 is a reduced-depth unit with a top-mount fan. This means it's only 100 mm long and 125 mm wide. At 63.5 mm tall, height is uniform across all SFX power supplies.

We like that this model can deliver full power continuously even at up to 50°C ambient. Conversely, two negatives include its sleeve bearing fan (though it's made by a top-notch manufacturer) and short warranty. When the competition is offering seven years of coverage, SilverStone needs to at least step up with a five-year warranty. Right now it's being much more conservative with its guarantee, which hurts the SX550's perceived reliability.

Power Specifications

Rail3.3V5V12V5VSB-12V
Max. PowerAmps2122452.50.3
Watts12054012.53.6
Total Max. Power (W)550

The minor rails offer 120 W of maximum combined output, while the +12V rail can deliver almost all of the unit's power on its own. The 5VSB rail is fairly typical for a modern PSU; SilverStone states that its peak amperage is 3 A.

Cables And Connectors

Native Cables
DescriptionCable CountConnector Count (Total)
ATX connector 20+4 pin (300mm)11
4+4 pin EPS12V (400mm)11
6+2 pin PCIe (400mm+150mm)12
SATA (320mm+200mm+100mm)13
Four-pin Molex (320mm+200mm) / FDD (+200mm)12 / 1

The number of SATA connectors is low for a 550 W PSU, and the same goes for its four-pin connectors. Since this is a small power supply without modular cables, SilverStone chose not to overload it. We can understand that sentiment, though the ATX cable is very short. We're pretty sure it'll have a lot of compatibility problems with most mid-tower cases. All connectors use standard 18-gauge wires, which are recommended by the ATX spec.

Power Distribution

Since this PSU features a single +12V rail, we do not have anything to say about its power distribution.

MORE: Best Power Supplies

MORE: Power Supplies 101

MORE: How We Test Power Supplies

MORE: Picking The Right Power Supply: What You Should Know

MORE: All Power Supply Content

This thread is closed for comments
15 comments
    Your comment
  • turkey3_scratch
    It doesn't seem like Silverstone can get anything right these days. I don't see how they can't include a rubber grommet where the wires leave the cage. When people are bending those wires around the case, they can easily rub up against a sharp edge like that and cut through the insulation or even damage the wires and increase the resistance. For $95 this is a rip off, I think it should be priced at $75. It's pretty loud, too.

    Also, according to your thing the PS113 doesn't support OTP, even though this unit seems to. It also seems to support UVP. Doesn't quite make sense to me. http://www.tomshardware.com/reviews/power-supplies-101,4193-22.html
  • Aris_Mp
    Most supervisor ICs don't support OTP, so this protection is implemented through other circuits in PSUs that actually have OTP.
  • Clamyboy74
    Having few cables is the point of an sfx psu. Sfx cases don't have much driver space, and short wires are good for small cases. Who in their right mind would but an sfx psu for use in a mod tower case, especially with a $95 price tag? When you review sfx psu's please bear into consideration that these are made for use in small cases, where short cables, few connectors are deal breakers for consumers. Thank you.
  • turkey3_scratch
    The thing that hurts this unit is that there is no common hardware configuration that will fit into an SFX case and require more than a 400W power supply like the Corsair SF which is much better. Most high-end AMD GPUs like the R9 390 are just way too large to even fit into an SFX case. If you think of cards that can actually fit into an SFX case, they are going to be small form factor cards, which are almost always under 200W, or these days even quite less. CPU overclocking to extremes can't be done in SFX cases with limited cooler sizes and due to airflow restrictions, so, really, I don't see a position in the market where this unit can be competitive over the Corsair SF400. And since this unit does not come with an SFX to ATX bracket, it is implied that nobody will probably install it into a case that takes an ATX PS2 power supply.
  • AlistairAB
    I have the corsaif sf450 and can confirm it blows the silverstone out of the water (silverstone never fixed their fan problems with their sfx psus)
  • Samer1970
    1712875 said:
    The thing that hurts this unit is that there is no common hardware configuration that will fit into an SFX case and require more than a 400W power supply like the Corsair SF which is much better. Most high-end AMD GPUs like the R9 390 are just way too large to even fit into an SFX case. If you think of cards that can actually fit into an SFX case, they are going to be small form factor cards, which are almost always under 200W, or these days even quite less. CPU overclocking to extremes can't be done in SFX cases with limited cooler sizes and due to airflow restrictions, so, really, I don't see a position in the market where this unit can be competitive over the Corsair SF400. And since this unit does not come with an SFX to ATX bracket, it is implied that nobody will probably install it into a case that takes an ATX PS2 power supply.


    how about Titan X Pascal cards / 1080 ti? They consume 435Watt total System power.
  • turkey3_scratch
    Not quite samer and not cards that would fit in an SFX case.

    Also, my bad guys, I meant SF450 not 400.
  • Samer1970
    1712875 said:
    Not quite samer and not cards that would fit in an SFX case. Also, my bad guys, I meant SF450 not 400.


    maybe you should check the following cases :

    http://www.fractal-design.com/home/product/cases/node-series/node-202

    http://www.silverstonetek.com/product.php?pid=533

    http://www.silverstonetek.com/raven/products/index.php?model=RVZ02

    https://www.ncases.com/

    https://www.dan-cases.com/
  • turkey3_scratch
    If you own a 1080Ti why would you get a mediocre PSU like this anyway? Once again, it doesn't seem to have a purpose at all. Once power requirements get anywhere past 300W you probably have high-end hardware in which case a unit like this is a poor choice over the SF600.

    Budget power supplies over 500W really have no place in this world. People purchase budget power supplies over 500W for three reasons:

    1) They have high end hardware and underestimate the need for a quality PSU
    2) They are uninformed and think "more watts" is better.
    3) They overestimate their power requirements.

    I suppose you could argue if they have 225W of hardware a 550W unit like this is perfect in terms of efficiency. Okay, maybe so. But that depends on how much you value efficiency, I suppose.

    The unit still performs poorly compared to Corsair. It's true, Corsair SF dominate the SFX market with the best units.
  • Samer1970
    1712875 said:
    If you own a 1080Ti why would you get a mediocre PSU like this anyway? Once again, it doesn't seem to have a purpose at all. Once power requirements get anywhere past 300W you probably have high-end hardware in which case a unit like this is a poor choice over the SF600. Budget power supplies over 500W really have no place in this world. People purchase budget power supplies over 500W for three reasons: 1) They have high end hardware and underestimate the need for a quality PSU 2) They are uninformed and think "more watts" is better. 3) They overestimate their power requirements. I suppose you could argue if they have 225W of hardware a 550W unit like this is perfect in terms of efficiency. Okay, maybe so. But that depends on how much you value efficiency, I suppose. The unit still performs poorly compared to Corsair. It's true, Corsair SF dominate the SFX market with the best units.


    Does not need to be 1080 ti , any 250 watt GPU card ... from 390 , 390x to others .. there are people on budget and use such cards in compact systems .

    I just mentioned gtx 1080 ti as a modern example ..
  • turkey3_scratch
    Well you may have a point. The unit is still underwhelming for the price, though. I don't think an R9 390 is a wise choice for a compact case anyway, seeing it can get quite hot. But to be honest a Corsair SF 450 can handle an R9 390 with a locked Intel CPU. Yeah, it'll push it hard but it'll still be quieter than this unit. I could never use this loud of a PSU on a system of mine. Should be very reliable from the fan RPM but still super loud.
  • Samer1970
    1712875 said:
    Well you may have a point. The unit is still underwhelming for the price, though. I don't think an R9 390 is a wise choice for a compact case anyway, seeing it can get quite hot. But to be honest a Corsair SF 450 can handle an R9 390 with a locked Intel CPU. Yeah, it'll push it hard but it'll still be quieter than this unit. I could never use this loud of a PSU on a system of mine. Should be very reliable from the fan RPM but still super loud.


    Have you seen the NCASE M1 ? it is very popular and it can run any card inside cool...

    I do agree that better power supply is the way to go (if you are rich) , but this power supply is good and does have a market .

    One more thing to add , Short cables are huge problem and hard to find ... and sadly they only come with SFX power supply for free .. many compact Micro ATX cases with full ATX power supply have a huge problem fitting the long cables , alot of people buy the SFX with ATX bracket for this reason (Corsair does not include it ) ...

    and a set of short cable are minimum $30 , and only Silverstone sell those for their ATX power supplies ... If you do it yourself it will cost you $5 per cable ...

    I wish for an important thing in Modular power supplies : PUT 2 SETS of CABLES PLEASE , SHORT and LONG .
  • turkey3_scratch
    2 sets of cables costs a lot more money than you think. You can order custom length cables from websites for certain PSUs.

    For most people, it really doesn't matter if the cables are a little too long since what's important to them is more their computer and that it works.
  • JQB45
    If I were to rank this 1 being best 5 being horrible I'd give it a 3.5.
  • Su
    It's noisy, so I won't buy it.