SilverStone SX650-G PSU Review: Lots Of Power In A Small Form Factor

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By Aris Mpitziopoulos
published

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Efficiency, Temperature & Noise

Efficiency

Our efficiency testing procedure is detailed here.

Using results from the previous page, we plotted a chart showing the SX650-G’s efficiency at low loads, and loads from 10 to 110 percent of its maximum-rated capacity.

Image 1 of 4

Measured efficiency under normal loads was high enough. However, it didn't look as good under light loads, at least compared to competing models with similar specifications.

Efficiency At Low Loads

In the following tests, we measure the SX650-G's efficiency at loads significantly lower than 10 percent of its maximum capacity (the lowest load the 80 PLUS standard measures). The loads we dial are 20, 40, 60, and 80W. This is important for representing when a PC is idle, with power-saving features turned on.

Swipe to scroll horizontally
Test #12V5V3.3V5VSBDC/AC (Watts)EfficiencyFan SpeedPSU NoisePF/AC Volts
11.207A0.491A0.475A0.196A19.70063.287%1117 RPM19.4 dB(A)0.883
12.109V5.072V3.349V5.114V31.128115.17V
22.436A0.980A0.983A0.391A39.74967.701%1117 RPM19.4 dB(A)0.967
12.109V5.070V3.345V5.100V58.713115.17V
33.672A1.475A1.494A5.093A59.86881.586%1117 RPM19.4 dB(A)0.977
12.095V5.068V3.344V5.093V73.380115.17V
44.895A1.975A1.974A0.786A79.78183.941%1117 RPM19.4 dB(A)0.981
12.091V5.065V3.340V5.087V95.044115.17V

With 20W and 40W of load, we would like to see efficiency levels close to 70% and 80%, respectively. Also, the fan's speed was fairly high in these tests. It could have started spinning at a slower speed.

5VSB Efficiency

The ATX specification (revision 1.4), along with CEC, ErP Lot 3 2014 and ErP Lot 6 2010/2013, states that 5VSB standby supply efficiency should be as high as possible, recommending 75 percent or higher with 550mA, 1A, and 1.5A of load. The PSU should also achieve higher than 75% efficiency at 5VSB under full load, or with 3A if its maximum current output on that rail is higher than 3A.

We take six measurements: one each at 100, 250, 550, 1000, and 1500mA, and one with the full load the 5VSB rail can handle.   

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Test #5VSBDC/AC (Watts)EfficiencyPF/AC Volts
10.102A0.52172.061%0.114
5.130V0.723115.15V
20.252A1.29076.558%0.218
5.124V1.685115.16V
30.542A2.77379.776%0.314
5.114V3.476115.16V
41.002A5.11280.593%0.376
5.101V6.343115.16V
51.502A7.63780.670%0.408
5.086V9.467115.17V
62.501A12.61179.290%0.442
5.042V15.905115.17V
Image 1 of 2

The 5VSB rail achieved high efficiency scores with 115V input.

Power Consumption In Idle And Standby

In the table below, you'll find the power consumption and voltage values of all rails (except -12V) when the PSU is idle (powered on, but without any load on its rails), and the power consumption when the PSU is in standby mode (without any load, at 5VSB).

Swipe to scroll horizontally
Mode12V5V3.3V5VSBWattsPF/AC Volts
Idle12.117V5.075V3.353V5.127V5.1630.453
115.2V
Standby0.0850.014
115.2V
Image 1 of 2

The SX650-G's power consumption in standby is low enough with 115V input and a bit higher with 230V.

Fan RPM, Delta Temperature, And Output Noise

Our mixed noise testing is described in detail here.

The first chart below illustrates the cooling fan's speed (in RPM), and the delta between input and output temperature. The results were obtained at 37°C (98.6°F) to 47°C (116.6°F) ambient temperature.   

The next chart shows the cooling fan's speed (again, in RPM) and output noise. We measure acoustics from one meter away, inside a hemi-anechoic chamber. Background noise inside the chamber is below 6 dB(A) during testing (it's actually much lower, but our sound meter’s microphone hits its floor), and the results are obtained with the PSU operating at 37°C (98.6°F) to 47°C (116.6°F) ambient temperature. 

The following graph illustrates the fan's output noise over the PSU's operating range. The same conditions of the above graph apply to our measurements, though the ambient temperature is between 30°C (86°F) to 32°C (89.6°F).  

The PSU's lowest output noise was less than 20 dB(A). At normal operating temperatures, it remained there up through 270W of load. With 40 to 50W more, the 30 dB(A) mark was passed quickly. And beyond 390W, the SX650-G found itself in the 35-40 dB(A) region.

SilverStone's fan profile could be tuned better. After all, noise output increased by 15 dB(A) within a 50W range. We did notice that if load on the minor rails remained below 70W combined, the fan spun slower (even under high operating temperatures).

MORE: Best Power Supplies

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Aris Mpitziopoulos
Contributing Editor

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

See more Power Supplies Reviews
8 Comments Comment from the forums
  • termathor
    Hey,

    I'm surprised a PSU with 85 degrees caps *and* only 3 years warranty is given such a good score ...
    Reply
  • jimmysmitty
    21233248 said:
    Hey,

    I'm surprised a PSU with 85 degrees caps *and* only 3 years warranty is given such a good score ...

    What I found interesting is the praise he gives the SF600 here yet the review he did of it gives it the same score as this unit, 7/10.

    He also had a ton of cons on the SF600 review that are just, well sorry but some are stupid. No Berg Adapter? Who even needs one of those these days? I doubt this PSU even has a berg adapter.

    So why does the SF600 which has better components (105c caps) and a better warranty (5 years) AND performs better apart from a heavier load on the not as used 5v and 3.3v rails causing the fan to spin up rate the same as this PSU?

    As mentioned in the article as well its cheaper and the Platinum version is, if you can find it, MSRP $10 bucks more (I found the Silverstone for $20 bucks less than the SF 600 Platinum on Newegg) and it has even better performance, components and a 10 year warranty.

    So again, how does this rate a 7/10 like a better PSU?
    Reply
  • crmaris
    When you criticise that someone talks stupid, you should be extra careful not to fall into the same trap :)

    Berg adapter, there are still some people that want it so why not include it? From the moment it is an adapter (so it doesn't alter the modular cables) and only costs some cents.

    The final rating isn't up to the performance only! But the overall picture including the product's usability. The SF600 is a great unit but has a major flaw. It only has two PCIe connectors! So you cannot fully utilize its 600W max power. While on the contrary the SilverStone unit has four of them. To give you an example it has exactly the same cable configuration with the SF450.

    Please take a better look at the epilogue of each of the reviews and you will get the meaning. The ratings are just a number to provide a rough idea and nothing more. Else I wouldn't bother write so much in the end of each review and list or pros and cons.
    Reply
  • jimmysmitty
    21233851 said:
    When you criticise that someone talks stupid, you should be extra careful not to fall into the same trap :)

    Berg adapter, there are still some people that want it so why not include it? From the moment it is an adapter (so it doesn't alter the modular cables) and only costs some cents.

    The final rating isn't up to the performance only! But the overall picture including the product's usability. The SF600 is a great unit but has a major flaw. It only has two PCIe connectors! So you cannot fully utilize its 600W max power. While on the contrary the SilverStone unit has four of them. To give you an example it has exactly the same cable configuration with the SF450.

    Please take a better look at the epilogue of each of the reviews and you will get the meaning. The ratings are just a number to provide a rough idea and nothing more. Else I wouldn't bother write so much in the end of each review and list or pros and cons.

    Was not stating that the person was stupid. Just that the con was stupid as the berg connection is not used in the majority of PC products much like how Molex is dying off in favor of the SATA connector. I have not seen a berg connection in a modern PC build for some time.

    As for the PCIe connectors, that's a fair "con". Notice I didn't mention it. I don't even think you can buy one like it for Corsairs PSUs and the only one I can think might have had a split single cable was the older CX series although I would personally never use one.

    So if we look at cons, then why did the SF600 get "dinged" for not having a ATX adapter but this did not?

    BTW I was incorrect. The SF600 has a 7 year warranty not 5. That's more than double, better grade components and cheaper. When I look at a PSU the biggest concern is build quality. Sure it would be nice to have some of the extras but I personally think build quality is the most important part. This PSU has a lower grade build, less warranty but hey it includes an out dated adapter and you can hook up two higher end GPUs to it so it rates the same.

    I personally don't feel like the two PSUs are in the same class nor deserve the same rating. To each their own.

    Let me clarify my reasoning. I don't want to sound like a jerk. Users will utilize this as a solid rating and a reason to buy or not buy. They wont always read the entire verdict or review.

    It is much like Amazon or Newegg reviews. People will look at the average star rating. They wont actually look at the actual reviews and if a product has 1000+ reviews I don't blame them however sometimes you can go into a product and look at the review and see that it may have no bearing on the products actual quality.

    Basically having a PSU that has lower performance, lower warranty and lower quality components rated the same as another with better quality will lead people who are not in depth tech savvy people to think they could buy either one and get the same quality.

    If you do feel that the rating/score is that unimportant than maybe the end should consist of pros/cons and a verdict with no score? However I do suggest to keep the pros and cons consistent as nicking one PSU for one thing but the other not feels a bit off.
    Reply
  • Dark Lord of Tech
    I have the SF600 it's a gem , the best in it's class in my opinion.
    Reply
  • Dark Lord of Tech
    Nice review , thanks ARIS!
    Reply
  • SilverStone Guy
    21233924 said:
    I personally think build quality is the most important part. This PSU has a lower grade build, less warranty but hey it includes an out dated adapter and you can hook up two higher end GPUs to it so it rates the same.

    I personally don't feel like the two PSUs are in the same class nor deserve the same rating. To each their own.

    In regards to build quality, the SX650-G is no less than that of SF600, besides the bulk cap being lower in temperature rating at 85C (which itself is a high quality brand and part btw, and we do extensive testing to make sure cooling is sufficient for it to last), everything else on the PCB is on par or better. And besides the core components, we've shown over at jonnyGURU, the fan we used in SX650-G is definitely better than SF600. The cables we included are also arguably better quality as well because they are more flexible.

    Many people don't realize increasing power output by 50W in SFX at the current 600W+ level is much more difficult of an engineering exercise than for ATX PSUs. I think in some ways this review article is also at fault for marginalizing SX650-G's 50W power increase over the SF600. Our SX600-G was released in 2014 and SX650-G in 2017, so that means it took three years to make an SFX PSU more powerful by 50W (while making it perform better, quieter, with more connectors, etc...) for around the same price!
    Reply
  • jimmysmitty
    21239216 said:
    21233924 said:
    I personally think build quality is the most important part. This PSU has a lower grade build, less warranty but hey it includes an out dated adapter and you can hook up two higher end GPUs to it so it rates the same.

    I personally don't feel like the two PSUs are in the same class nor deserve the same rating. To each their own.

    In regards to build quality, the SX650-G is no less than that of SF600, besides the bulk cap being lower in temperature rating at 85C (which itself is a high quality brand and part btw, and we do extensive testing to make sure cooling is sufficient for it to last), everything else on the PCB is on par or better. And besides the core components, we've shown over at jonnyGURU, the fan we used in SX650-G is definitely better than SF600. The cables we included are also arguably better quality as well because they are more flexible.

    Many people don't realize increasing power output by 50W in SFX at the current 600W+ level is much more difficult of an engineering exercise than for ATX PSUs. I think in some ways this review article is also at fault for marginalizing SX650-G's 50W power increase over the SF600. Our SX600-G was released in 2014 and SX650-G in 2017, so that means it took three years to make an SFX PSU more powerful by 50W (while making it perform better, quieter, with more connectors, etc...) for around the same price!

    Ok if you state the parts are equal to or better than a review by the same guy should result in an equivalent or better score correct?

    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=533

    http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story6&reid=477

    Even if you go through the SF600 got better performance numbers throughout, even hitting almost platinum efficiency.

    Yes FDB is better. The Corsair is able to run fanless in low loads so its a trade off.

    The cables are very objective. These days a lot of people swap the cables out with colored individually sleeved ones.

    This review had this that concerns me:

    Sky-high OPP and OCP on the 3.3V and 5V rails
    Over-temperature protection doesn't appear functional

    Not bashing it. Just based on the reviews I found outside of this one show it isn't the same grade as the SF600 Gold unit. If you feel it is truly equal or better then the numbers need to prove it where it counts, the performance. Cables and fans are one side. They don't always outweigh the cons though. I also think that if you feel that way that the warranty should match.
    Reply