SilverStone SX650-G and SX500-G Reviewed

We would like to thank SilverStone for providing us with review samples of their SX650-G and SX500-G units. Without their generosity, this power supply review would not be possible.

The world of SFX power supplies has come along leaps and bounds in the past few years, leading to more and more powerful small form factor builds gracing our community. One of the leading manufacturers in the field, Silverstone, has recently added two more products to their lineup – the SX650-G and the SX-500G.

First showcased in 2016 and again at CES 2017, the impressively specc’d SX650-G reaches as high as 819 watts per liter in power density – besting even the 775 watts per liter figure offered by SilverStone’s flagship SX800-LTI, which James reviewed here. In this combined review, we are going to put both the SX650-G and SX500-G units to the test, side-by-side.

Here are few valuable resources from SilverStone’s website should you require some additional information:
SX500-G product page
SX500-G manual

SX650-G product page
SX650-G manual

A disclaimer first before we get started: SFF Network does not currently possess the expertise or equipment to fully test the electrical performance of PC power supplies, and as such, this article should not serve as the sole data point in determining whether to purchase this product. We’ll be able to contextualize the utility and experience of using this unit with others in the market place, but we’d suggest having our own review supplement those by others who have the hardware and capability to do more thorough analysis of electrical performance, especially at higher wattages.

Specifications for the SX650-G

Model No.	SST-SX650-G
Max. DC Output	650W
Power density	819W per liter
Load Range
+3.3V +5V +12V1 +5VSB -12V Max.(Amps) 22A 22A 54.2A 2.5A 0.3A Peak (Amps) / / / / / Min.(Amps) 0A 0A 0A 0A 0A Range (%) ±3% ±3% ±3% ±5% ±10% Line Reg.(%) ±1% ±1% ±1% ±1% ±1% Ripple(mVp-p) 50mA 50mA 120mV 50mV 120mV
Color	Black (Lead-Free Paint)
combined +3.3, +5V	110W
Combined +12V	650W
Input Voltage	90 ~ 264 Vrms
Input Frequency Range	47Hz ~ 63Hz
PFC	Active PFC (PF>0.9 at full load)
Efficiency	87%~90%（20% to 100% loading）
MTBF	100,000 hours
Operating temperature	0°C ~ 40°C
Protection	Over Current Protection Over Power Protection Over Voltage Protection Short Circuit Protection Under Voltage Protection Over Temperature Protection
Connectors	1 x 24 / 20-Pin motherboard connector (300mm) 1 x 8 / 4-Pin EPS / ATX 12V connector (400mm) 2 x 8 / 6-Pin PCIE connector (400mm / 150mm) 2 x 8 / 6-Pin PCIE connector (550mm / 150mm) 6 x SATA connector (“300mm / 220mm / 100mm” x 2) 3 x 4-Pin Peripheral connector (300mm / 200mm / 200mm) 1 x 4-Pin Floppy connector (100mm)
Cooling System	Single 92mm silent fan
Form factor	SFX
Noise Level	18 dBA minimum
Dimension	125 mm (W) x 63.5 mm (H) x 100 mm (D) 4.92″ (W) x 2.5″ (H) x 3.94″ (D)
Weight	1.36 kg
Certification	80 PLUS Gold

Specifications for the SX500-G

Model No.	SST-SX500-G
Max. DC Output	500W
Power density	630W per liter
Load Range
+3.3V +5V +12V1 +5VSB -12V Max.(Amps) 22A 22A 41.7A 2.5A 0.3A Peak (Amps) / / / / / Min.(Amps) 0A 0A 0A 0A 0A Range (%) ±3% ±3% ±3% ±5% ±10% Line Reg.(%) ±1% ±1% ±1% ±1% ±1% Ripple(mVp-p) 50mA 50mA 120mV 50mV 120mV
Color	Black (Lead-Free Paint)
combined +3.3, +5V	110W
Combined +12V	500W
Input Voltage	90 ~ 264 Vrms
Input Frequency Range	47Hz ~ 63Hz
PFC	Active PFC (PF>0.9 at full load)
Efficiency	87%~90%（20% to 100% loading）
MTBF	100,000 hours
Operating temperature	0°C ~ 40°C
Protection	Over Current Protection Over Power Protection Over Voltage Protection Short Circuit Protection Under Voltage Protection Over Temperature Protection
Connectors	1 x 24 / 20-Pin motherboard connector (300mm) 1 x 8 / 4-Pin EPS / ATX 12V connector (400mm) 1 x 8 / 6-Pin PCIE connector (400mm) 1 x 8 / 6-Pin PCIE connector (550mm) 6 x SATA connector (“300mm / 220mm / 100mm” x 2) 3 x 4-Pin Peripheral connector (300mm / 200mm / 200mm) 1 x 4-Pin Floppy connector (100mm)
Cooling System	Single 92mm silent fan
Form factor	SFX
Noise Level	18 dBA minimum
Dimension	125 mm (W) x 63.5 mm (H) x 100 mm (D) 4.92″ (W) x 2.5″ (H) x 3.94″ (D)
Weight	1.35 kg
Certification	80 PLUS Gold

Packaging and contents

Both the SX650-G and SX500-G power supplies are encased by a full color (matte, not glossy) cardboard package. Both units have a very similar looking exterior with the large model number being the only visual difference from afar.
The packaging did a great job protecting the internals during shipping and beyond a slight marred corner on the SX500-G, there was no damage to report.

Marketing material and additional specifications in various languages are included on the backside.

Internally, the power supply is held securely by high-density foam and is partitioned away from the slew of cables by a U-shaped sheet of cardboard. Atop that is a well presented black and white manual as well as some additional marketing material. The quality of the paper stock was immediately apparent when I removed it from the box. I know it might sound funny but when a company puts that additional effort into simple things like that, when they absolutely don’t need to, it goes a long way with me.

Included in the box is the power supply itself, the modular cable set in all-black, a small manual and advertising material, 4 black case screws (not pictured) and a power cable (not pictured).
The only thing missing here is an SFX to ATX bracket, but we’ve come to discover that’s normal procedure with all SFX units from SilverStone so we won’t discredit them for that (they just won’t get those bonus points).

Cables

The cable sets are unique between the two units, with the SX650-G offering a second PCIe cable, enough to support a dual-GPU configuration within the limits of a 650 watt PSU. The lengths of the remaining cables are the same between the SX650-G and SX500-G. Worth noting is that the 24-pin cable is only 300mm long so I wouldn’t recommend using these units in most full size ATX chassis (Editor: But that’s not applicable to SFFn readers is it?).

SX650-G Cable lengths are as follows:
1 x 24 / 20-Pin motherboard connector (300mm)
1 x 8 / 4-Pin EPS / ATX 12V connector (400mm)
2 x 8 / 6-Pin PCIE connector (550mm / 150mm)
2 x 8 / 6-Pin PCIE connector (400mm / 150mm)
6 x SATA connector (“300mm / 220mm / 100mm” x 2)
1 x 4-Pin Floppy connector (100mm)*
3 x 4-Pin Peripheral connector (300mm / 200mm / 200mm)*

*= Not included in the diagram.

SX500-G Cable lengths are as follows:
1 x 24 / 20-Pin motherboard connector (300mm)
1 x 8 / 4-Pin EPS / ATX 12V connector (400mm)
1 x 8 / 6-Pin PCIE connector (550mm)
1 x 8 / 6-Pin PCIE connector (400mm)
6 x SATA connector (“300mm / 220mm / 100mm” x 2)
1 x 4-Pin Floppy connector (100mm)*
3 x 4-Pin Peripheral connector (300mm / 200mm / 200mm)*

*= Not included in the diagram.

Often times, I’ve seen members on various forums mention that the SilverStone cables are easier to bend/organize than the Corsair cables. Now, having played with them both side-by-side, I can fully agree with that. Silverstone’s 24-pin cables are arranged in a way that definitely make for tighter bends for such an unwieldy cable. That being said SilverStone’s included accessory cables bent only slightly more than Corsair’s. I will let you be the judge by looking at the tight bends I was able to achieve with both 8-Pin PCIe cables.
Silverstone on the left – Corsair on the right.

The memory of each modular cable is great, so if ever you need to route the cable and have it stay put, it will listen.

Pinout Diagrams

The Power Supplies

Both units are extremely hard to tell apart. To the left is the SX650-G and on the right is the SX500-G.
Right off the bat, we’re very pleased to see that SilverStone managed to source an extremely small power switch versus the behemoth that was included on the SX800.

Also, unlike the earlier prototypes as well as the flagship SX800 unit, SilverStone has opted to use a flush fan grill that has been stamped out from the steel sheeting. They did this to ensure that the SFX PSU would stay within the required SFX specification as the grill stuck out ever so slightly to avoid butting against the fan. This is a slight disappointment as the wire grill looked more premium and typically provides better airflow (and as a result less noise) but we really appreciate their transparency disclosing all the iterations that their team went through to make this possible. We’ll find out if the noise is bearable later on (hint: it is).

Outside of the color coding for the PCIe connectors, as well as the unique pin-count and pin-shapes, there are no silk-screened markings on the chassis to indicate what goes where but there is a little diagram that is adhered just below the modular connectors. Unless you try to force things where they don’t belong, in pitch darkness, this shouldn’t be an issue.

Here is a closeup!

I’m always blown away by how small the SX650-G and SX500-G units are compared to a standard length ATX power supply (in this case, the Seasonic PRIME 650). So cute!
 

Measurements

No review on this site would be complete without them!

Here we can see that there is exactly 10mm of keepout from the edge of the housing to the edge of the C14 connector.

Here is a measurement from from tip-to-tip of the fan blades -we already knew it was a 92mm fan but felt like measuring it anyway.

Height

Depth

Width

Testing

As mentioned at the beginning of the review, we currently lack the expertise and equipment to properly evaluate the electrical performance of power supplies to a complete extent, so the following data is more to demonstrate that the SX650-G and SX500-G are capable of powering the test system with no issues.

Test Hardware

Intel i7-4770k @ 4.4GHz
ASUS Maximus VI Impact
MSI R9-280X Twin Frozr
2x 8GB G.SKill TridentX 2400MHz
Corsair Hydro Series H80i
1x 120mm Noctua NF-F12
1x 2.5″ 128Gb Kingston HyperX SSD
1x 3.5″ 1TB WD Blue HDD

Testing equipment

• Meterk 30-130dB(A) LCD Digital Sound Level Meter -used to measure the audio levels of the fan speeds at various temperatures, 30CM from the back of the PSU housing.
• HDE Professional Digital Infrared Photo Tachometer – non-contact tachometer, used to measure the fan RPM.
• Leaton 4 Channel K Type Digital Thermometer Thermocouple -used to measure ambient, intake, and exhaust temps.
• APC XS 1300 UPS – used to measure the AC draw of the system.
• Craftsman 65EA Multimeter – used to measure the PSU’s 12v.

Software used

• Furmark ver 1.19.0.0
• Prime 95 ver 29.3

Methodology

Each test is run for 10 minutes and then readings are taken before moving on to the next test.
For Prime 95 testing, we run the indicated number of threads in Blend mode.
For Furmark testing, we run Furmark on the GPU at the various resolutions (1080p and 1440p).
This will typically push a system well past usual levels and should provide a decent increase in not just voltage but also fan noise and heat output.

If this doesn’t abuse the PSU’s enough, I will find a system that will.

Test Results

SX650-G results

Wattage (AC)	Ambient Temp	Intake Temp	Intake Delta	Exhaust Temp	Exhaust Delta	Fan RPM	dB @ 30cm	12V	Test
83W	23.3°C	22.2°C	1.1°C	23.0°C	0.3°C	1194 RPM	45dB	12.12V	Idle
133W	23.3°C	22.6°C	0.7°C	27.5°C	4.2°C	1224 RPM	45dB	12.13V	2 threads of Prime95 Blend
150W	23.5°C	24.5°C	1.0°C	28.8°C	5.3°C	1233 RPM	45dB	12.13V	8 threads Prime95 Blend
400W	23.5°C	24.9°C	1.4°C	29.7°C	6.2°C	1868 RPM	47dB	12.14V	8 threads Prime95 Blend + FurMark 1080p
430W	23.7°C	25.2°C	1.5°C	30.3°C	6.6°C	1870 RPM	47dB	12.14V	8 threads Prime95 Blend + FurMark 2160p

SX500-G results

Wattage (AC)	Ambient Temp	Intake Temp	Intake Delta	Exhaust Temp	Exhaust Delta	Fan RPM	dB @ 30cm	12V	Test
83W	23.5°C	23.9°C	0.4°C	25.5°C	2.0°C	866 RPM	45dB	12.22V	Idle
133W	23.7°C	23.7°C	0.0°C	25.9°C	2.2°C	866 RPM	45dB	12.22V	2 threads of Prime95 Blend
150W	23.8°C	23.9°C	0.1°C	26.5°C	2.7°C	871 RPM	45dB	12.23V	8 threads Prime95 Blend
400W	23.9°C	24.3°C	0.4°C	27.2°C	3.3°C	1993 RPM	47dB	12.19V	8 threads Prime95 Blend + FurMark 1080p
430W	23.9°C	25.1°C	1.2°C	28.4°C	4.5°C	2012 RPM	47dB	12.19V	8 threads Prime95 Blend + FurMark 2160p

Fans

Both SFX power supplies are cooled by a 9-blade fluid dynamic bearing fan -a terrific choice for those that desire longevity and low noise. It’s a big upgrade from the cheap sleeve bearing that we found in the SX800. These FDB fans will easily outlast SilverStone’s 3-year warranty. C’mon SilverStone, you can’t be, “The standard SFX power supply benchmark” with just a 3 year warranty -these units are built far better than that!

The SX650-G uses a custom made DC12V .45A fan – model number S0921512HB.
This fan earned a LAMBDA-S+ rating from Cybenetics.
Cybenetics efficiency and noise level certificate for this exact power supply can be found here: https://www.cybenetics.com/d/cybenetics_MpN.pdf

The SX500-G uses a custom made DX12V .23A fan – model number S0921512MB
This fan earned a LAMBDA-S++ rating from Cybenetics.
Cybenetics efficiency and noise level certificate for this exact power supply can be found here: https://www.cybenetics.com/code/pdf.php?id=5U0

Noise

Noise levels were stellar across the board – zero complaints. The ambient room decibels were read at 45dB and only saw a jump of about 2dB during stress testing. The fans have a very pleasant hum to them that is anything but annoying -roughly equivalent to the pleasant whir of a high quality Noctua fan.

At no point in time did the fans turn on and off or oscillate up and down in speed. The sound was consistent during normal operation. I would have liked to have seen a semi-silent mode with these units but the fans were so incredibly quiet that it wasn’t needed.
While I was only able to push 430 watts with my current testbench hardware, it’s clear that the FDB fans are doing a terrific job keeping both thermals and noise to a minimum.

Protections

Using a heatgun (overkill, I know), I was able to verify that Over Temp Protection works, and the PSU shut off as expected. The system would not power back up right away, but after unplugging and replugging the power cord, the system turned back on without issue.

According to SilverStone’s product specs, both units also feature Input Protection, Output Protection, Over Voltage Protection, Over Power Protection, Short Circuit Protection, and Over-Current Protection.

The Internals

The case can be opened up to access the internal fan. This is great should you ever need to replace the fan or need to clean the internal components of any dust.

Now, as a full disclaimer, I’m not even going to pretend to know what it is that I am looking it here. I’m not an electrical engineer by any stroke of delusion nor would I consider myself an expert or power supply enthusiast (…yet?). If you want to know more about the internals of this PSU, that’s what JonnyGuru is for, and it’s why the site has earned our respect throughout the years. Ultimately, I just care that it powers a rig, that all the safety features work, and that it’s quiet. But for those of you who came here to see the guts, have at it!

Disconnecting the fan is really simple and the layout of everything is just… immaculate. It’s quite possibly the most beautiful layout I have ever seen. Amazing job from Sirfa!
We’ve seen some real ugly betty’s in the past here, here, here, here, and here. Hopefully those scarring images (sorry!) will help you appreciate just how beautiful these Sirfa units are.

There’s some neat looking green coils surrounding a GS-l x2 .47µF safety suppression capacitor.
  

They went the extra mile to include a matte black heatsink over the MOSFETs. It’s not burly but the arching positioning of it just under the fan would prove quite effective.
I didn’t have the heart to extract the PCB from either chassis so if you absolutely need to see the solder quality and or pictures of the daughterboards, I’ve let you down here.
 

This would be the Rubycon 470µF main filter cap and just below that would be the power factor correction controller.

I took this picture to showcase the completely unobstructed ventilation towards the back. Rigid, modern, and functional.

Can you spot the difference between the SX650-G and SX500-G? Outside of the slightly staggered caps in the center, I certainly couldn’t.

Pros

• Packaging is more than sufficient. Everything was secure and there was no damage to report.
• The PSU housing is easy to open and maintain without voiding the warranty.
• Quite possibly the best internal layout I’ve ever seen in a power supply.
• High quality internal components, oozing with quality.
• Fluid dynamic bearing Fans are a huge plus. I hope to see this is in all units going forward.
• First unit to break the coveted 800w per liter mark (SX650-G).
• Small power button is a welcome feature.
• Terrific documentation is included and the paper stock used goes way beyond what was expected.

Nitpicks

• No included ATX to SFX mounting bracket.
• No semi-fanless mode.
• No native support for dual EPS motherboards (especially now that their is an mATX Threadripper motherboard)

Cons

• 3 year warranty.

Conclusion

I think it goes without saying that I was extremely impressed with both the SX650-G and SX500-G. In construction they are both incredibly well made, in parts there were no sacrifices made, and in function they were just flawless. I would have zero problems recommending either of these two units for your next SFF project.

The only real con that we feel obligated to report is that Silverstone has decided to stick with a 3-year warranty compared to the 7-year warranty that Corsair offers with their $120 SF600 unit. Ultimately, I will leave the decision up to you whether saving $10 to lose 50 watts but gain an additional 4-year warranty period is worth it. Personally, I care more about stable power delivery, headroom for the sake of efficiency, and a quality fan more than some warranty that I hope to never use. That being said, you really cannot go wrong with either of SilverStone or Corsair’s offerings.

These units mark a terrific evolution from SilverStone’s previous departures as they have completely eliminated all the flaws that we encountered in previous units. We have watched SilverStone evolve and we’re excited to see what they come out with next.

At time of the writing, the SX650-G can be purchased from Amazon for $130 and the SX500-G can be purchased from Amazon for $105

Thoughts? Please post them on the forums here and be sure to thank @Silverstone for making these products for our community.

This review sample was provided by SilverStone.

Here at SmallFormFactor.net we give manufacturers the ability to be part of the community. We offer a right to reply to our hardware reviews. If a manufacturer responds with any feedback or corrections, their comments will be posted here.