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
Hot Test Results
The electrical performance of the SilverStone SX800-LTI is not greatly improved over that of the slightly older SilverStone SX700-LPT, but there is a small improvement on the output power quality. Voltage ripple figures are adequate, with our instruments recording a maximum of 36 mV, 40 mV and 32 mV on the 12V, 5V and 3.3V lines respectively. The paradox here is that the main 12V line seems to be much better filtered than the minor 5V/3.3V lines, which seem to have been somewhat neglected, perhaps because the designer just could not find enough space for more filtering components. Voltage regulation is good, with the 12V line maintaining a regulation of 2.2%. The 3.3V/5V lines are falling slightly behind, with the regulation at about 2.4%.
| Main Output | ||||||||
| Load (Watts) | 162.8 W | 404.87 W | 603.21 W | 796.4 W | ||||
| Load (Percent) | 20.35% | 50.61% | 75.4% | 99.55% | ||||
| Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts | |
| 3.3 V | 1.5 | 3.41 | 3.74 | 3.39 | 5.61 | 3.34 | 7.48 | 3.33 |
| 5 V | 1.4 | 5.1 | 3.51 | 5.07 | 5.26 | 5.03 | 7.01 | 4.98 |
| 12 V | 12.34 | 12.2 | 30.84 | 12.14 | 46.27 | 12.06 | 61.69 | 11.94 |
| Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
| 20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
| 3.3V | 2.6% | 22 | 24 | 26 | 32 | 16 | 26 |
| 5V | 2.4% | 20 | 30 | 32 | 40 | 18 | 26 |
| 12V | 2.2% | 16 | 22 | 30 | 36 | 36 | 22 |
Although the SX800-LTI is rated for operation up to 40°C, the unit had little trouble operating inside our hotbox. Naturally, the energy conversion efficiency took a measurable hit and the average efficiency across the nominal load range dropped down to 91.6%. The reduction of the unit’s efficiency is somewhat greater at higher loads, suggesting that the active components are slightly stressed by the high ambient temperatures.
The internal temperatures of the SX800-LTI, while it was operating in our hotbox, were surprisingly low. PSUs usually reach temperatures exceeding 80°C under these operating conditions, but the SilverStone SX800-LTI hardly reached up to 75°C under maximum load. This time the cooling fan started even sooner, when a load just higher than 120 Watts. The thermal control of this unit is very aggressive, probably because SilverStone did not want to risk reducing its reliability over better acoustics performance.
Under these high temperature conditions, the cooling fan of the SX800-LTI not only starts sooner but also immediately increases its speed to audible levels. Inside the hot box, the PSU is louder with a load of just 200 Watts than with a load of 550 Watts in room temperature. As the load increases, the speed of the fan constantly increases as well, reaching its maximum possible speed when the load exceeds 700 Watts. Thankfully our hotbox test is one of extremes and that - outside of poorly ventilated cabinets - few home users have environments this warm, as the sound pressure levels with a load above 500 Watts under these conditions would be practically intolerable for home users.
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WithoutWeakness - Thursday, January 18, 2018 - link
Now that we have multiple options for medium-to-high output SFX power supplies I would like to see more case manufacturers design cases that drop ATX support and only support SFX PSUs. It's been amazing to see the designs that smaller case makers and newcomers have made when designing for the smallest cases possible and SFX PSUs have enabled them to dedicate less space for bulky ATX PSUs.DanNeely - Thursday, January 18, 2018 - link
On larger cases saving an inch on the PSU is a much smaller return than it is on mITX systems. Between the higher prices and much lower availability of SFX/SFXL PSUs I don't think we'll ever see widespread adoption of them in mATX/ATX cases.jtd871 - Thursday, January 18, 2018 - link
WithoutWeakness wasn't talking about larger cases. He was talking about cases without support for ATX PSUs.cjb110 - Friday, January 19, 2018 - link
Not sure they can do that and still call it an ATX case, which then makes marketing a potential nightmare, that might be one reason.Valantar - Monday, January 22, 2018 - link
There are a couple from Lian Li, and the Kimera Industries Cerberus is nice (if you can get it), but yeah, the selection is limited. I'd love to see more SFX+mATX or SFX+ATX cases. Why not?jrs77 - Thursday, January 18, 2018 - link
I've got the 500W SFX-L PSU from Silverstone and it's the sweetspot for a single GPU-system imho.meacupla - Thursday, January 18, 2018 - link
At this wattage, it's more like "We crammed in 800W, because we could".Even if you assembled the most powerful mITX system, using an Asrock X299E-ITX, an i9-79xx and 1080Ti and overclocked those, you would still be inside of 600W power envelope at full load.
(Going off of Coolermaster's power calculator)
edzieba - Thursday, January 18, 2018 - link
Don't forget SFF cases for mATX and ATX. While 800W is not enough for the quad Titan-V beast (smallformfactor DOT net/forum/threads/kimera-industries-cerberus-the-18l-matx-usa-made-enclosure.454/page-180#post-78461), you you drop back to a mere two Titan Vs - either on an mATX board or with ITX and PCIe Bifurcation - you can cram serious compute into an even smaller case.jordanclock - Thursday, January 18, 2018 - link
Because conversion efficiency is best at about 50% load, so you use a PSU like this to stay within the most efficient load range.Holliday75 - Thursday, January 18, 2018 - link
How much does that translate in savings on my electric bill? How quickly would that offset the cost of a higher wattage PSU running more efficiently?