The SilverStone SX800-LTI SFX-L 800W PSU Review: Big PSU, Small Niche
by E. Fylladitakis on January 18, 2018 9:00 AM EST- Posted in
- Cases/Cooling/PSUs
- SilverStone
- SFX
- SFX-L
Cold Test Results
For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.
The SilverStone SX800-LTI is surprisingly efficient, even for an 80Plus Titanium certified unit. We recorded an average efficiency across the nominal load range (20% to 100% of the unit's capacity) of 93%, with the unit maintaining a conversion efficiency above 94% when the load is between 300 and 500 Watts. The low load efficiency is relatively good but there is room for improvement, as the efficiency drops below 80% with loads lower than 40 Watts.
SilverStone designed the SX800-LTI to be semi-fanless, i.e. the fan only spins when the load or temperatures are high enough to necessitate it. 80Plus Titanium units usually work in fanless mode with a load up to several hundreds of Watts. The cooling profile of the SX800-LTI is way more aggressive than most, starting the fan when the load is higher than just 200 Watts, even when the temperatures are low. Still, that is high enough to generally ensure that the fan will never spin-up when the system is idling or performing simple tasks.
The sound pressure readings are a little higher than what we would like from a unit that is most likely going to be installed in HTPC systems, but they are not unnatural for a compact PSU with such a massive power output. Even when it fan starts spinning, the SX800-LTI maintains comfortable user levels with loads up to 550-600 Watts in room temperature. The PSU does get loud when heavily loaded, but it is highly unlikely that this PSU will ever find itself running at such loads for prolonged periods of time.
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Meaker10 - Friday, January 19, 2018 - link
It can help room temperatures and with a small forn factor case it could make a difference to internal temperatures.sonny73n - Friday, January 19, 2018 - link
@meaker10Huh? PSU & temperatures? What?!
DanNeely - Friday, January 19, 2018 - link
All the power lost due to PSU inefficiency is extra heat added to the room. When it's cold it works like supplemental furnace/etc (if electric heat is cost effective depends on what the other heat source is); in the summer it's just more heat for the AC to push out of the building.meacupla - Saturday, January 20, 2018 - link
But if a 600W PSU is pulling 90% efficiency at 400W, where as this 800W PSU is pulling 94% efficiency at 400W, the 600W would be consuming 444W, versus the 800W would be consuming 425W.A 19W difference is hardly going to result in a noticeable difference inside the case, since PSUs only expel heat.
Macpoedel - Tuesday, January 23, 2018 - link
According to Silverstone's charts the 500W SFX-L PSU is 91% efficient at a 400W load (with a 230V AC input voltage), this 800W PSU is 95 % efficient at the same load. That comes down to 439W and 421W from the wall, let's take 20W for simplicity.If the PC were to have a continuous load of 400W all year long, that makes 175.2 kWh. In my country electricity is pretty expensive, around 0.21€/kWh (probably a bit more now, 0.21 was a few years ago).
175.2 kWh would then cost €36.7, but the price difference between the 500W and 800W variant is around €100, so you'd need about 3 years of continous load at 50% to benefit from the better efficiency.
Let's also assume this PSU isn't powering a mining rig but a workstation, that gets used around 8 hours a day, that makes 9 years before the higher efficiency pays off. I doubt many PSU's are used for longer than that.
Also, in most cases a 400W continuous load is a very unrealistic assumption, most pc's idle most of the time, even workstations (and this is not a server PSU). Below 20% load, both PSU's have pretty much the same efficiency.
So when exactly does the higher efficiency pay off for pc's that don't have a continuous load? Pretty much never...
Much more important are the warranty and component quality, and it's not like the 800W PSU is so much better in those regards, it's not going to last longer, the chances of failure are the same.
I'd even argue in favor of a 80Plus Bronze PSU instead of 80Plus Gold, because those gains in efficiency are very slim as well, but then component quality often is a bit worse and the warranty period goes down to 3 years or lower, so paying more for better quality makes sense there (for the same capacity!)
Now if you want your workstation to consume as little power as possible, be my guest and pay double the price for a PSU that only has to deliver half of its capacity at most, just don't expect the investment to pay off.
Macpoedel - Tuesday, January 23, 2018 - link
Oh when I say 175.2 kWh, I'm talking about that 20W power difference between 91 and 94% efficiency, not total consumption, that would cost a lot more than €36 of course.Foeketijn - Friday, January 19, 2018 - link
I think it would be more likely be, because it is far more easy to get the titanium certification on a high powered psu. There is a reason why there are no affordable high efficiency low powerd psu's.The Benjamins - Thursday, January 18, 2018 - link
It only having 1 4+4 EPS sucks, you can't use this for the AsRock X399M board in a CaseLabs Bullet BH4.PeachNCream - Thursday, January 18, 2018 - link
The article's title is like a perfect TL;DR summary. As far as SFX goes, it's a small niche product. I can't think of too many system builds that would require that much power output inside a small enough case, that also supports the larger-than-SFX physical dimensions.Lau_Tech - Thursday, January 18, 2018 - link
These "stuff i found in my attic" reviews are really blockbuster stuff, eh?