Silverstone SX1000 Review – 969W per Liter!

Introduction

So far, we’ve mostly covered various ATX units… So, let’s change things up a bit and cover something smaller. With a density of almost 1000w per liter, the SX1000 is impressive on its own already, but how does it hold up? Let’s have a look at this 230 USD SFX-L PSU!

General Specifications

BrandSilverstone
ModelSST-SX-LPT
Wattage1000W
Introduction year2020
ModularityFully
Warranty10 years

Power Specifications

3.3V5V12V5VSB-12V
25A25A83.3A3.0A0.3A

Cables

Cable typeCable QuantityConnector Per Cable
ATX 20+4 pin11
EPS12v 4+4 pin21
PCIe 6+2 pin32
SATA24
4-pin Peripheral13
4-pin Floppy11

The SX1000’s cables are shorter than you usually find with ATX PSUs, but this makes sense. The unit is meant for smaller formfactor cases, which can make it challenging to manage away the cable length you normally find with ATX PSUs. I had no issue with the length in my Alta G1M, as seen in our review of the case.

Otherwise, the unit features two EPS cables and 3 PCIe cables, making it able to support high end systems. The only thing I would’ve liked to see are individual 8 pin PCIe cables instead of using two on a single cable. However, this makes it hard to connect more than one GPU to the SX1000, so I do understand Silverstone’s choice here.

The cables are using 16 AWG wires, something that should be expected at 1000w, but is not a given. Very nice to see!

External

Ah, good ol’ hexagons, little restriction on the intake with a metal frame… Perfect. The housing has a simple, but effective look. No unnecessary restrictions, no overly fancy top grill. Everything to like so far.

The unit is so small, it can be held in one hand… though it’s a bit heavy to hold that way. I honestly have nothing to complain here… Even though I destroyed two of the screws on the side of the unit to get it open. But this isn’t something I should complain about, people shouldn’t open their own units. Let me be the idiot to do that. Speaking of opening units, let’s go to look at the protections of the SX1000.

Protections

OPPYes (WT7527RA)
OCPYes (WT7527RA, UP3861P)
OTPNo*
UVPYes (WT7527RA, UP3861P)
OVPYes (WT7527RA, UP3861P)
SCPYes (WT7527RA)
MOVYes

The OTP of the SX1000 is likely integrated into the protection IC, but has been tough to see functioning. My own OTP testing hasn’t matured enough yet to use for this review, and in Aris’ review the OTP didn’t trigger. I do hope to be able to follow this up and show results down the line. Otherwise, everything we should expect here is integrated into the protection IC (WT752RA) and DC-DC controller (UP3861P).

Parts Breakdown+Internal

OEMEnhance Electronics
PlatformUnknown
Input Voltage100-240VAC
Primary ConverterAPFC Full Bridge LLC
RectifierSynchronous Rectification
RegulatorDC-DC
FanGlobe Fan B1201512HB
BearingDouble Ball Bearing (DBB)
PCB TypeDouble Sided
Bulk Capacitor(s)2x Rubycon USK (400V, 470uf, 85c)
APFC MOSFETs2x Infineon IPW60R099C6
APFC Boost DiodeUSCi UJ3D06520TS
Resonant ControllerATK AT6103ZSPC
Main Switches4x Toshiba TK20A60W
12v MOSFETs8x Infineon BSC014N04LS
DC-DC Converters4x Infineon BSC018NE2LS
DC-DC ControlleruPI Semi uP3861P
Supervisor ICWeltrend WT7527RA
Standby PWM ControllerATK AT6002H

The SX1000 is made by Enhance, a manufacturer best known for working with the likes of Thermaltake, Lian Li and Cooler Master, but also have a long track record with Silverstone. They focus on server-oriented PSUs and mainly produce midrange and higher end platforms.

Enhance has always had an interesting style of making heatsinks. Especially in older high-power units like the #1300GT (Zalman Acrux, SS Strider Platinum PT, TT Toughpower Grand Platinum =>1000W, Gigabyte XP-M 1200, TT TP Grand Plat FM), they chose to use massive, distinctive heatsinks to cool the unit. Here too we can see quite the interesting heatsink style used on the unit.

The fan used is a Globe Fan B1201512HB, a slim double ball bearing fan. With the height limitations SFX-L gets you into, manufacturers often have a hard time with bigger parts like the bulk capacitors. That’s why Silverstone solved part of this with using a 15mm thick fan. instead of a 25mm fan like usual. The Double ball bearing makes the SX1000 a bit louder than most other units with either a FDB or rifle bearing fans, but offers a higher lifespan.

Moving to the main capacitors, we see two Rubycon capacitors. It’s odd to see 85C capacitors used in a unit like this, they should have a high enough capacity to hold up (pun intended) to the ATX specification and leave an offline UPS to get a battery backup running before the unit shuts down on power loss. It would also be nice to see 420V rated capacitors being used, but considering the production date is slightly older and there’s a shortage of these going on, this is not something I’ll complain too much about for now.

The APFC FETs are two high-end MOSFETs by Infineon combined with a boost diode from USCi. A powerful setup, as should be expected at this price.

For the main FETs, we see something interesting. While it’s expected of a higher wattage unit to have this in a full bridge, it’s rare to see this in compact units like this. But here we are, with a beautiful set of 4 Toshiba FETs.

Even more impressive is that Enhance was able to put two main transformers in parallel. This is again something that is often found in high wattage units, but is hard to do at this power density.

Eight Infineon BSC014N04LS FETs handle the 12v rail, with four Infineon BSC018NE2LS FETs handling the 5V and 3.3V rail on the daughterboard. This is controlled by a UPI Semi UP3861P controller.

The unit uses high-quality parts that are expected at this price and wattage, but in an incredibly compact setup.

Electrical Performance

The following results are by third party PSU lab Cybenetics. The results shown are based off the SX1000 Platinum report published on 14-04-2021.

Test Equipment

Electronic loadsChroma 63601-5 x4
Chroma 63600-2 x2
63640-80-80 x20
63610-80-20 x2
AC SourcesChroma 6530
Keysight AC6804B
Power AnalyzersN4L PPA1530 x2
Sound AnalyzerBruel & Kjaer 2270 G4
MicrophoneBruel & Kjaer Type 4955-A
Data LoggersPicoscope TC-08 x2
Labjack U3-HV x2
TachometerUNI-T UT372 x2
Digital MultimeterKeysight U1273AX
Fluke 289
Keithley 2015 - THD
UPSCyberPower OLS3000E 3kVA x2

Overall (115v)

Average efficiency90,063%
Efficiency at 2% load68,474%
Average efficiency 5VSB84,311%
Standby power consumption0,060536 W
Average PF0,987
Average noise output36,09 DB
Efficiency rating (ETA)Platinum
Noise rating (LAMBDA)Standard+

Overall (230v)

Average efficiency92,148%
Average efficiency 5VSB83,354%
Standby power consumption0,01051610 W
Average PF0,935
Average noise output36,23 DB
Efficiency rating (ETA)Platinum
Noise rating (LAMBDA)Standard+

Efficiency (115v)

Load (115v)EfficiencyAC (Watts)DC (Watts)
20w load68,474%29,17019,974
40w load76,265%52,40039,963
60w load81,921%73,23659,996
80w load83,499%95,74879,949
10% load83,572%119,62199,970
20% load90,951%219,884199,987
30% load91,798%326,744299,945
40% load91,952%434,297399,346
50% load91,913%543,426499,479
60% load91,554%654,922599,606
70% load90,932%769,081699,343
80% load90,289%885,741799,723
90% load89,653%1.002,918899,150
100% load88,978%1.123,409999,586
110% load88,291%1.245,4041.099,577
Crossload 184,960%148,467126,137
Crossload 289,390%1.010,5331.130,474

Efficiency (230v)

Load (230v)EfficiencyAC (Watts)DC (Watts)
20w load69,000%28,75219,982
40w load78,535%50,89639,971
60w load82,155%73,03460,001
80w load84,787%94,29879,952
10% load84,575%118,22099,985
20% load92,540%216,127200,005
30% load93,528%320,724299,966
40% load93,750%426,115399,483
50% load93,771%532,785499,597
60% load93,611%640,647599,713
70% load93,171%750,716699,453
80% load92,715%862,662799,813
90% load92,403%973,103899,181
100% load92,001%1086,542999,628
110% load91,634%1200,0271099,636
Crossload 186,083%146,568126,170
Crossload 292,415%1093,9221010,949

Voltage Regulation (115v)

Load (115v)12V (voltage)5V (voltage)3.3V (voltage)5VSB (voltage)
20w load12.080V5.061V3.351V5.092V
40w load12.074V5.058V3.348V5.086V
60w load12.067V5.056V3.346V5.080V
80w load12.064V5.050V3.342V5.075V
10% load12.058V5.048V3.340V5.069V
20% load12.048V5.032V3.327V5.058V
30% load12.036V5.024V3.319V5.046V
40% load12.032V5.016V3.312V5.034V
50% load12.025V5.008V3.303V5.022V
60% load12.011V4.999V3.294V5.009V
70% load11.999V4.990V3.286V4.997V
80% load11.987V4.981V3.277V4.984V
90% load11.976V4.973V3.269V4.976V
100% load11.961V4.964V3.260V4.955V
110% load11.944V4.956V3.252V4.946V
Crossload 112.036V5.011V3.310V5.076V
Crossload 211.968V4.989V3.281V5.006V

Voltage Regulation (230v)

Load (230v)12V (voltage)5V (voltage)3.3V (voltage)5VSB (voltage)
20w load12.075V5.060V3.350V5.092V
40w load12.067V5.057V3.348V5.086V
60w load12.063V5.055V3.346V5.080V
80w load12.059V5.049V3.341V5.074V
10% load12.060V5.048V3.340V5.069V
20% load12.050V5.032V3.327V5.057V
30% load12.038V5.024V3.319V5.045V
40% load12.039V5.015V3.310V5.033V
50% load12.025V5.007V3.302V5.021V
60% load12.012V4.999V3.294V5.008V
70% load12.000V4.990V3.285V4.996V
80% load11.989V4.981V3.276V4.983V
90% load11.978V4.973V3.268V4.975V
100% load11.963V4.963V3.259V4.953V
110% load11.951V4.956V3.252V4.946V
Crossload 112.036V5.010V3.309V5.076V
Crossload 211.972V4.989V3.281V5.005V

Ripple (115v)

Load (115v)12V5V3,3V5VSBPass/Fail
10% load14.20mV6.90mV10.80mV9.30mVPass
20% load19.90mV8.60mV12.20mV10.80mVPass
30% load26.40mV9.60mV13.50mV12.50mVPass
40% load31.30mV10.20mV14.60mV14.10mVPass
50% load36.40mV11.00mV15.90mV14.90mVPass
60% load40.20mV11.30mV16.70mV16.70mVPass
70% load46.70mV12.40mV17.70mV17.90mVPass
80% load53.70mV12.60mV19.90mV19.50mVPass
90% load60.20mV13.40mV20.70mV20.00mVPass
100% load71.70mV14.50mV22.40mV22.70mVPass
110% load81.80mV15.20mV23.20mV24.50mVPass
Crossload 121.60mV9.70mV16.90mV11.70mVPass
Crossload 272.40mV14.00mV20.40mV22.60mVPass

Ripple (230v)

Load (230v)12V5V3,3V5VSBPass/Fail
10% load14.00mV6.40mV10.40mV8.90mVPass
20% load19.70mV8.00mV12.50mV10.20mVPass
30% load27.00mV9.30mV13.00mV11.90mVPass
40% load31.40mV9.70mV14.50mV14.20mVPass
50% load35.70mV10.30mV15.50mV14.60mVPass
60% load41.00mV11.10mV16.50mV16.60mVPass
70% load46.70mV11.20mV17.70mV17.70mVPass
80% load52.90mV11.80mV19.40mV18.50mVPass
90% load58.70mV12.70mV20.60mV19.40mVPass
100% load69.90mV13.80mV22.40mV22.30mVPass
110% load77.20mV14.50mV23.90mV23.10mVPass
Crossload 121.80mV9.30mV16.30mV9.90mVPass
Crossload 269.10mV12.90mV19.60mV22.00mVPass

Fan Speed/Noise (115v)

Load (115v)RPMNoise (DBa)
20w load0<6.0
40w load0<6.0
60w load0<6.0
80w load0<6.0
10% load0<6.0
20% load0<6.0
30% load0<6.0
40% load101823.7
50% load102524.0
60% load103423.4
70% load167340.7
80% load208245.5
90% load220447.6
100% load220247.5
110% load220147.2
Crossload 10<6.0
Crossload 2219947.2

Fan Speed/Noise (230v)

Load (230v)RPMNoise
20w load0<6,0
40w load0<6,0
60w load0<6,0
80w load0<6,0
10% load0<6,0
20% load0<6,0
30% load0<6,0
40% load102223,9
50% load102824
60% load103223,4
70% load163939,6
80% load204444,4
90% load222047,1
100% load221347,4
110% load220847,7
Crossload 10<6,0
Crossload 2221047,3

Hold-up Time (230v)

Hold-up time (ms)18.80
AC loss to PWR-OK hold up time (ms)1.30
PWR_OK inactive to DC loss delay (ms)17.5

Conclusion

The SX1000 is a very interesting unit, especially considering there’s nothing like it on the market right now. It has an incredible power density, an open design, high quality parts and small case-friendly cables that supports most high-end hardware. It truly is a foot of engineering.

However, we are unable to verify the unit’s OTP, which isn’t a huge concern with the high reliability of the fan, but is and should be considered the norm today. Some of the electrical performance has room for improvement and the fan kicks in aggressively with the high density of parts.

If you do need a high density 1000w unit, the SX1000 is your only option right now, and a solid one at that. But with competition from Cooler Master coming in with a 1100w and 1300w unit, this can get interesting.

For our alternatives we chose to compare it to compact ATX units and 750/850w SFX units below.

Silverstone SX1000

Buy SX1000
Pros:
  • Solid part choice
  • Extremely high power density
  • High durability
  • Solid electrical performance
Cons:
  • Unable to confirm OTP functioning as expected
  • Fan kicks in aggressively
  • 12V Ripple at higher loads should be more tight

Alternatives

SFXCompact ATX (<=160mm)

Corsair SF Platinum

Buy SF750
Pros:
  • More compact
  • Overall best electrical performance at the time of writing
  • Individually sleeved cables
  • Loads of options for third party cables with the use of the Corsair Type 4 pinout
  • Widely covered by reviewers
Cons:
  • Expensive
  • No 850w option
  • Smaller fan

 

Pros:
  • 850w option
  • White and black versions
  • Often found cheaper than SF750
  • Widely covered by reviewers
Cons:
  • Early batches had a weirdly set semi-passive curve
  • Louder than Corsair SF
  • Smaller fan

 

Lian Li SP

Buy SP750
Pros:
  • Often found cheaper than SF750
  • Widely covered by reviewers
Cons:
  • No 850w option
  • Very aggressive fancurve
  • Smaller fan
Pros:
  • Very compact for ATX
  • 1000w and 13000w options
  • Solid electrical and noise performance
  • Widely covered by reviewers
Cons:
  • Recently released, making it harder to find
  • Expensive

 

BeQuiet Pure Power 11 FM

Buy Pure Power 11 FM 1000W
Pros:
  • Widely covered by reviewers
  • Solid electrical and noise performance
Cons:
  • Recently released, making it harder to find
  • Different design from the 550/650/750w units

 

Chieftec PowerPlay Platinum

Buy Powerplay 1050W
Pros:
  • Widely covered by reviewers
  • Solid electrical performance
Cons:
  • Loud
  • Chieftec mainly sells in Europe

 

EVGA G6

Buy G6 1000W
Pros:
  • Widely covered by reviewers
  • Solid electrical and noise performance
  • Often found on sale
Cons:
  • Potentially sensitive to GDDR6X Ampere GPU due to 12v sensing issues on Seasonic units

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