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SilverStone ST45SF-G 450W SFX Form Factor PSU Review

Manufacturer: SilverStone

DC Load Regulation

DC Output Load Regulation

One of the first things we want to see is how well the PSU can regulate the DC outputs and maintain stable voltages.  To simulate real world and maximum loading conditions, the SilverStone SFX PSU was connected to the load testers and supplied with a constant 115 VAC.  In this test we are interested in seeing how well a PSU can maintain the various output voltages while operating under different loads. 

The ATX12V V2.2 tolerance for voltages states how much each output (rail) is allowed to fluctuate and has tighter tolerances now for the +12V outputs.  I have also included a second table of expanded tolerances (±1% to ±6%) for reference.

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The following tables list the DC voltage results for the PSU while operating on 115 VAC, 60 Hz.

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The ST45SF-G produced very good load regulation on all of the outputs across the entire load range; even when delivering the maximum rated capacity of 450 watts DC power.  And the three primary outputs stayed within SilverStone’s claims of ±3%; very good.

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DC Output Line Regulation

In this test we are interested in seeing how well a PSU can maintain the various output voltages while the AC input line voltage changes.  In the previous Load Regulation test, the AC line voltage was held constant at 115 VAC.  Now we will look at how much the DC outputs change as the load is held constant and the AC line voltage is changed from 120 VAC down to 90 VAC.

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The Line Regulation test was performed with the combined DC loads set to 338W.  The AC input voltage to the power supply (via the Extech power analyzer) was adjusted using a Powerstat variable autotransformer.  We observed virtually no measurable change in the PSU's DC outputs. 

Cross-Loading Test

PC switching mode power supplies provide multiple DC output voltages.  Ideally, the total load should be distributed across all the main outputs (+3.3V, +5V, +12V).  This means that the combined +3.3V and +5V load should be proportional to the combined +12V load – as one increases, so should the other.  Unfortunately, this is not always the case, especially in newer PCs that predominately use +12V and may put only minimal loads on the +3.3V and/or +5V rails. 

Cross-loading refers to imbalanced loads.  If a PC pulls 400W on the +12V outputs and only 40W (or less) on the combined 3.3V and +5V outputs, the resulting voltage regulation may suffer.

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The SilverStone ST45SF-G PSU didn't have any problems handling our cross-loading tests.  In the first test we put a heavy load on the +12V outputs and a light load on the remaining outputs.  In the second test we reversed the cross-load and placed a heavy load on the +3.3V and +5V outputs with a light load on the +12V rail.  Once again, the PSU passed this test without problems.

November 6, 2012 | 09:23 AM - Posted by Kenneth (not verified)

I bought a Silverstone Strider ST50F-P psu about 2 years ago for a home server build. I bought it specifically to fit into a Lian Li PC-V354 case which has the psu standing on end over the mobo while looking at it from the side. I wanted a nice short psu that wasn't going to be tasked with high demand of power and it fit the bill. If I were to do it all over again, I am not sure I would go with this unit that was reviewed. While it is 40mm shorter overall and would give me a little bit more room to work in that particular case, it also has a 40mm smaller fan. I use that fan to pull air from the inside to the outside and the size trade off would be pretty steep. I guess this would be nice for a mini ITX build where space is at a super premium but otherwise I would still grab something with more air flow.

November 9, 2012 | 02:27 AM - Posted by Justin 150 (not verified)

I think the noise is the main issue here. Seems very well designed.

If you are not pulling more than 150W on load then a pico-psu is probably a better option. Even at 225W the Silverstone seems pretty quiet but from there upwards the noise seems to increase pretty rapidly.

If needing 300W + and have the space there are better options

November 19, 2012 | 05:29 AM - Posted by Robert123 (not verified)

Perfect upgrade for the sg05 & 06. esp if you have the older 300w versions.

December 31, 2012 | 06:40 AM - Posted by David López (not verified)

Be careful!. I have SG06, and this Power supply modular need some depth extra mm, because the connector is big than normal version.
It can be fit, but you need to make a lot of force, and curve a lot the wires, isn't god the modular version because need more space.

Other part is that the sound is horrible!, make a lot of plus sound than the standard version, even at 60-90W only of consumption!.
If you need more than 140W is horrible loud!

I open the power supply, and first I try to mount the fan outside the power supply chassis, and decrease some little db, because the little grid on intake increase loud, and the grid on outside pard not increase as intake. This decrease a little, but not to much, but you need 15mm extra of space, and be care of obstruction fan, and lost warranty of you new power supply.....

Today I will go to buy a fan for replace, I check this models that can be well (3000rpm models):

http://www.sunon.com/pro.php?c1=16
http://www.rexususa.com/fans/25816.html
http://www.rexususa.com/25816-1.html
http://www.nmbtc.com/fans/part-numbers/search/3106KL-05W-B50/5099

The stock fan reach 3500rpm at 42db, but I don't know cfm. I not remember the trademark, I thinbk was similar than rfl, but I remember has 4 letters not three. Personality, for some around 4€ extra Silverstone can be put a better fan, and better control of speed, I not trust never more on Silverstone specifications.... they can be crazy when was putting silent on your specifications!

Other part is the rpm control have fails, bacause when increase the power consumption increase the rpm (and loud), but when you recover a low consumptions the rpm not decrease at the initial levels, and was more louder than the same consumption of before...

I made another easy mod that not need broke anything, I put a 60x60x25 silent fan rear the power supply extracting the air, I attached with prolimatech magnetic supports.

Because I think is better always that the pressure need to be positive, I put this extracting fan at low rpm, then the intake fan capabilities are better than this outtake fan capabilities.
For better dissipation the fresh air need to stay some seconds or miliseconds and arrive to all deepth of power supply. This is thinked normally for a good heat dissipation on cars, and I think is ok also for computer or all that need heat disipation.

If you not need more than 300W, the standard version is better. I have i7-3770T(80W), and also plus GTX 660(140W) the standard 300W Power supply is suficient, with plus margin for sata devices.

I buyed only for gold plus certification and for better quietness sound of the standard version, and I think a was make big mistake for this caprice....

If i know all this before, I never buyed, because is truth that I not need....

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