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.

By Aris Mpitziopoulos
published

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Pros, Cons And Final Verdict

The SX550 is a budget-oriented PSU that, according to SilverStone, addresses mostly system integrators that need lower-priced parts. In order to make the SX550 more affordable (by SFX standards), FSP, which manufactures the power supply, employs an ACRF topology. This turns out to be the SX550's greatest weakness. Though it utilizes less expensive parts compared to half-bridge and full-bridge topologies, it simply cannot match their performance. As a result, you get lower efficiency, especially under higher loads, and a poor-performing +12V rail in transient loads. Conversely, this design proves to have better ripple suppression than the Enhance and Sirtec platforms that the SX600-G and SX500-LG models use. On top of that, FSP's platform has a higher temperature rating, at 50 ºC.

FSP is a large manufacturer with lots of experience in this field, that's for sure. But we strongly believe that its ACRF implementations need more work in order to be competitive. The SX550's pair of bridge rectifiers look weak, since they aren't bolted onto a heat sink. Moreover, the over-power protection's triggering point is set too high, allowing the +12V rail to fall close to 11 V when the PSU is overloaded. Meanwhile, ripple on the minor rails goes sky high. To add insult to injury, OPP doesn't activate even when the PSU is clearly taxed with close to 630 W, and according to the official specs, under-voltage protection isn't provided (though the ATX spec doesn't require it).

The lack of modular cables is a big let-down for us, and we don't like the fact that the fixed cables aren't sleeved all the way back into the chassis. The lack of a grommet around the cable exit hole doesn't look good either. If the SX550 was priced around $80, we would probably overlook some of its deficiencies. Priced at $95, however, it's dangerously close to Corsair's top-notch SF600, which offers much higher performance along with modular cabling and a larger fan that promises quieter operation. Given the minor price difference between Corsair's offering and the SX550, SilverStone's solution isn't very attractive. The company should adjust its price if it wants to make it more competitive. The provided warranty should be also increased to at least five years, given that the competition provides seven-year coverage.

The SFX landscape changed dramatically once Corsair got involved. SilverStone doesn't play alone any more, and it needs to adapt to this new reality if it wants to maintain market share. The SX550 needs several performance improvements or a significant price cut before we deem it worthy of your attention.

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Aris Mpitziopoulos
Aris Mpitziopoulos
Contributing Editor

Aris Mpitziopoulos is a Contributing Editor at Tom's Hardware US, covering PSUs.

15 Comments Comment from the forums
  • 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
    Reply
  • Aris_Mp
    Most supervisor ICs don't support OTP, so this protection is implemented through other circuits in PSUs that actually have OTP.
    Reply
  • 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.
    Reply
  • 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.
    Reply
  • 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)
    Reply
  • Samer1970
    18459920 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.
    Reply
  • turkey3_scratch
    Not quite samer and not cards that would fit in an SFX case.

    Also, my bad guys, I meant SF450 not 400.
    Reply
  • Samer1970
    18460559 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/
    Reply
  • 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.
    Reply
  • Samer1970
    18460649 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 ..
    Reply