Silverstone SFX SX800-LTI

[testman78]

Introduction

It's taking a while, but production of power supplies specifically targeting small form factor systems is slowly increasing, and this is a great thing in our humble opinion. Despite the reduction in size compared to ATX PSUs, SFX and SFX-L units still offer plenty of juice, easily enough for the type of system that most mid-range enthusiasts opt for i.e. a single GPU with a moderately overclocked mainstream CPU. Silverstone has been a manufacturer of SFX power supplies for some time now, with most of their units being supplied by Enhance. In today's review we are taking a look at the latest SFX PSU from Silverstone, the SFX SX800-LTI. The SX800-LTI model number translates to a 800W SFX-L Titanium-rated fully-modular power supply. It is also semi-fanless. This new unit is made by Enhance Electronics, unlike the previous top-model, the Platinum certified 700W SX700-LPT (made by Sirtec). Otherwise it is quite similar. It is actually quite interesting that Silverstone pretty much switches between Enhance and Sirtec for each new SFX/SFX-L unit.



There is only single +12V output of course, which delivers 66 A or 792 W so pretty much the whole power output. It can also provide some power for the DC-DC modules (16 A@+3.3 V, 15 A@+5 V or 80 W combined). The rest is pretty much the usual (0.3 A/−12 V, 2.5 A/+5 V SB). The list of protections has pretty much all of them and includes also OCP and OTP.




Packaging & Contents

The power supply comes packaged in a two-color cardboard box, which seems sturdy enough to protect the unit and its accessories. The front side of the packaging is simple, a general image of the power supply is used for showcase.



On the lower side, there are the name & capacity of the power supply along with a few of the product's features. Additionally, we see an 80 Plus Titanium badge.



On the top, we have the logo of the manufacturer.



Coming around to the back of the box is some marketing. Of particular interest to me is the tidbit that indicates that the fan should stay off up to about 30% utilization, and should still be below 1100 RPM at ~50% load.You will find the efficiency and fan speed curves, along with short descriptions of the unit's most notable features (like the fully modular design, flat and stealth cables, and the single +12V rail). In the right-bottom corner, on the back, SilverStone provides a version number that could come in useful in case you want to track platform changes and fixes.



Technical and power specification tables are on top of the package, along with the available connectors list. As mentioned on the back, this is a single-rail design, and the full 800W is available on the 12V. The number and type of connectors is suitable for a 800W PSU as well, though I question why a PSU that will presumably end up in a Mini-ITX or mATX case needs twelve SATA connectors.



On the sides of the box, there's only name & capacity of the power supply.



Opening up the box reveals some paperwork, cabling, and the PSU itself resting snugly in a block of closed-cell foam.



There is a yellow piece of paper wrapped around the PSU notifying you that the fan won't spin until a certain load or temperature is reached. You have to remove this, of course, before proceeding with the PSU's installation. Unfortunately, the SX800-LTI doesn't come with any kind of bag or pouch to store the unused modular cables. We'd like to see SilverStone ship the SX800-LTI with an SFX-to-ATX adapter in case you want to drop it into a normal ATX case.



Moving on, one of the manuals that comes with this unit is 10 pages long in English only and the other is 60 pages long in 10 languages just as we have seen before.



Among this total of 70 pages of literature, we find the pin out guide, power label, installation instructions, some trouble shooting steps, the very complete electrical specifications, and the warranty information.



All of the modular cables and the power cable are all inside a cardbox.



It's a little weird not seeing a bag come with a modular power supply for the extra cables. They also include a small baggie with black finished screws.



Beyond the additional wattage, the SFX SX800-LTI also stands out from the other SFX power supplies in the connections it has available. Beyond the normal 24-pin and 8-pin CPU connection. You end up with two PCI cables, each with two 6+2 connections to cover any variation on the 1 or 2 power plug video cards. This means you can handle two video cards, any other SFX power supply is only going to support one. You get one Molex cable with three connections on it and to go with it a 4-pin floppy adapter. Then the last three cables are all for SATA power connections. Each has three SATA power on it but one of the three cables is twice as long.



The SX800-LTI cables are the same flexible, ribbon-style cables that come with other SilverStone SFF power supplies. The SFX SX800-LTI has the thin cables. They are a lot easier to work with, more flexible, and don't require sleeving to look decent in your PC. The thickness is thick enough that you can even tuck them behind motherboard trays that don't normally support any cable management as well.




A Closer Look-Outside

The SilverStone SFX SX800-LTI obviously is very small compared to an ATX PSU, measuring in at the SFX standard dimensions of just 125 x 63.5 x 100 mm (WxHxD).



The overall appearance of the power supply is minimalist. Due to the limited internal volume the SFX form factor affords, most SFX PSUs come with a 60mm/80mm fan, so imagine our surprise at finding an double ball-bearing 120mm fan in the SX800-LTI. It is covered with your standard steel ring grill and it has the Silverstone snowflake logo right in the middle.



The casing has a satin black finish all over with the exception of the titanium lettering on the side sticker. The side sticker has a breakdown of the amperage for each rail as well as the wattage breakdown. The rest of the sticker is filled with all of the standard regulatory logos.



On the other side of the unit, we have three stickers. They indicates the SX800-LTI's version number, QA check and serial number. The rear panel has a regular hex hole pattern. A power switch is also fitted, which is a nice to have feature.



I really like the embossed Silverstone logo, it's simple and not to in your face.



Moving to the remaining side, we see the modular connectors and get a good look at the little plastic connector covers. I think this is a great idea because I could see where, in a cramped SFF build, there's the possibility of a stray wire or connector coming into contact with one of the unused PSU connectors and causing a short. The Silverstone SFX SX800-LTI is a full modular power supply including the 24-pin motherboard cable. To help there is a layout sticker under the connections that shows what each plug handles although other than the CPU and PCIe plugs there should be no confusion. To help with that Silverstone color coded the PCIe plug to match the cable as well.





A Look-Inside

The SX800-LTI model uses a platform proprietary of Enhance. The PCB has a reduced footprint, the internal components are arranged in a way to best utilize the small space available. All of capacitors used inside the PSU are Japanese made with a mix of solid polymer and electrolytic caps used throughout. The EMI filter includes two Y caps and two X ones on the first stage, and two Y caps, a single X one, two CM chokes, and an MOV on the second stage.



Enhance's soldering quality is good.



At the front side of the modular PCB, several Suncon polymer caps and a single electrolytic cap filter the rails.



The transient filter starts right at the AC receptacle. In this case, it includes two X and two Y caps. There are also two CM02X ICs that blocks current through an X cap's discharge resistor when AC voltage is connected, and automatically discharges the cap through the corresponding resistor when AC is disconnected.



The big let-down here is the quality of the bulk caps. They might be provided by Rubycon (one of the best cap manufacturers), but their maximum temperature rating is only 85C. According to the official specs, the USG Rubycon caps last 3000 hours at 85C, so we can calculate that their lifetime is around 2.12 years at 50C ambient using this formula, and with an assumed 10C increase in their operating temperature because of current ripple. A 105C cap with a 2000-hour rating has a 5.63 year lifetime under the same conditions. As you can see, the difference is huge. That's why we only want to see 105C caps on the APFC converter.



An NTC thermistor is used to lower the inrush currents. It is supported by a bypass relay, which lowers the thermistor's cool-down period and provides a small efficiency boost.



The PFC controller, a Champion CM6502 IC, is installed on a vertical PCB that resides on the secondary side.




Test System

In order to review power supplies the right way i needed some key pieces of equipment. Briefly those pieces of equipment are shown below.



SunMoon SM-8800 SMPS ATE
CSI3710A Programmable DC load (+3.3V and +5V outputs)
CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
Extech MultiMaster MM560 digital multimeter
Extech 380803 Power Analyzer
SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
Oscium iMSO-104 signal oscilloscope
Oscium WiPry-Combo peak power meter and spectrum analyzer
Sperry DT-506 4 Channel Digital Thermometer
Powerstat Variable Autotransformer, 1.4 KVA, 0-140 VAC


Voltage Variance

Load regulation is excellent with all rails exhibiting very minor fluctuation under load.




Cross Load

The Silverstone SFX supply handled the Cross load tests without any concerns.




AC Ripple

Noise suppression results are decent, with all rails falling within the rated tolerance guidelines. The +3.3V and +5V peak at 20mV at full load. The +12V rail hits a maximum of 45mV at 800 watts load.




Efficiency

Efficiency is very good, peaking at 94.29 percent at 50 percent load. This drops to around 92.68 percent at full load.




Temperature

The fan works well to expel heat out the rear of the chassis. The overall results are very good indeed.




Noise Level

Passive operation lasts up to around 250W of load. Afterwards, the fan spins slowly up to 500 W. With more than 500 W, its speed increases significantly. Beyond 600 W, the noise exceeds 44 dB(A). If you don't plan on pushing this power supply hard, expect it to run quietly. Otherwise, it can get loud.




Final Thoughts

SilverStone plays alone in the SFX field, at least when it comes to high-capacity models. The company has a rich portfolio with the SX800-LTI as its flagship. SilverStone is constantly pushing the power density scores of its SFX products higher, and the new SX800-LTI unit, is clear proof. This unit is the flagship of SilverStone's SFX-L models, and with 800W capacity, it's able to deliver up to 66 Amps on its single +12V rail. Despite its high power, it still uses a semi-passive mode that deactivates the fan under light loads, in order to offer a dead silent operation. The semi-passive mode lasts quite a while (250W) for a high-capacity PSU with restricted dimensions and an overpopulated PCB. Those obsessed with cable management will appreciate the all-modular flat cable design with multiple provided lengths of some cables. Despite its compact dimensions, the SX800-LTI achieves amazing efficiency, registering among the highest levels we've seen from an 80 PLUS Titanium power supply (even the ones based on an ATX form factor). What really stands out is the super-tight voltage regulation. Ripple suppression and overall efficiency are both stellar, and technically the unit didn’t exhibit any problems during our week long series of tests. In addition to stellar performance, the SX800-LTI power supply offers a full complement of safety and protection features. A couple of things could do with improvement though. We'd like to see SilverStone ship the SX800-LTI with an SFX-to-ATX adapter in case you want to drop it into a normal ATX case. Sure you can still buy an adapter (or make one), but this was an omission that was a poor decision. Also the two primary bulk caps are made by Rubycon and rated for 270uf, 420V, and 85C. While Rubycon is certainly a well respected brand, we are not thrilled with the choice of the less expensive 85C rating instead of 105C. The only real niggle we have is the very short 3 year warranty offered with this unit. You wouldn't expect it in a 174 Euro PSU. Many power supply warranties now are between 5,7 and 10 years, so 3 years does raise an eyebrow.



The SX800-LTI power supply has impressed us. The SilverStone SX800-LTI is the strongest SFX PSU available on the market today. If you’re in the market right now for an SFX form factor power supply your options are very limited to a handful of brands. Despite these limitations Silverstone have not been complacent at all: their SFX SX800-LTI is a high quality power supply unit that delivers excellent performance for its size. When small just isn’t small enough Silverstone’s SFX SX800-LTI Power supply offers a great solution to the space problem. If you’re building an ultra compact system you can be rest assured the SFX SX800-LTI will still provide you with high quality power, just in a smaller package.