PC Power & Cooling Silencer 910 Power Supply Review
By Gabriel Torres on July 24, 2009
PC Power & Cooling Silencer 910 uses internally the same design as Seasonic M12D, thus being manufactured by Seasonic. This design is based on a DC-DC converter on the secondary, i.e., Silencer 910 is basically a +12 V power supply with two small power supplies in charging of converting the +12 V output into +5 V and +3,3 V. This is the same concept used on power supplies series like Signature and TruePower New from Antec, M12D from Seasonic, UCP from Cooler Master and HX (750 W and above) from Corsair. These other models proved to have an above-the-average efficiency. It is important to keep in mind that other models from PC Power & Cooling Silencer series use a different internal design. Let’s see how the performance from PC Power & Cooling Silencer 910 is.
Silencer 910 is 80 Plus Silver certified, meaning it has a minimum efficiency of 85% under light load (20% load, i.e., 182 W) and under full load (910 W) and a minimum efficiency of 88% under typical load (50% load, i.e., 455 W).
PC Power & Cooling Silencer 910 is 7 1/8” (180 mm) deep, using a small 80 mm fan on its rear instead of a big 120 mm or bigger fan on its bottom, and featuring active PFC, of course. It doesn’t have a modular cabling system, being the main difference between Silencer 910 and Seasonic M12D series.
The cables that come with Silencer 910 are the following:
Usually on power supplies all cables have the same length, what doesn’t happen with Silencer 910. All wires are 18 WG, with the wires used on the main motherboard cable being thicker (16 AWG), which is great to see.
We think this power supply could have at least two extra cables for video cards. Since it is clearly targeted to high-end systems, it should bring direct support for SLI and CrossFire configurations using three high-end video cards, which is not the case. With only four video card connectors you can install up to two high-end video cards, since each video card requires two power connectors. You can install more than two video cards converting standard peripheral power plugs into video card auxiliary power connectors, though.
Now let’s take an in-depth look inside this power supply.
We decided to disassemble this power supply to see what it looks like inside, how it is designed, and what components are used. Please read our Anatomy of Switching Power Supplies tutorial to understand how a power supply works and to compare this power supply to others.
This page will be an overview, and then in the following pages we will discuss in detail the quality and ratings of the components used. The first thing that caught our attention was that this power supply was internally identical to Seasonic M12D.
As we have mentioned in other articles and reviews, the first place we look when opening a power supply for a hint about its quality, is its filtering stage. The recommended components for this stage are two ferrite coils, two ceramic capacitors (Y capacitors, usually blue), one metalized polyester capacitor (X capacitor), and one MOV (Metal-Oxide Varistor). Very low-end power supplies use fewer components, usually removing the MOV and the first coil.
On this power supply this stage is flawless. It has two extra ferrite coils, one extra X capacitor and two extra Y capacitors.
On this page we will take an in-depth look at the primary stage of PC Power & Cooling Silencer 910. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.
This power supply uses two GBU806 rectifying bridges in its primary, which one feeding a separated active PFC circuit, like it happens on Seasonic M12D. Each bridge supports up to 8 A at 100° C, so in theory, you would be able to pull up to 1,840 W from the power grid; assuming 80% efficiency, the bridges would allow this unit to deliver up to 1,472 W without burning them. Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply.
As mentioned, there are two active PFC circuits, each one using two SPP20N60C3 power MOSFET transistors, so we have a total of four MOSFETs on the active PFC stage. Each MOSFET is capable of delivering up to 20.7 A at 25° C or 13.1 A at 100° C in continuous mode (note the difference temperature makes) or 62.1 A in pulse mode at 25° C. These transistors present a maximum resistance of 190 mΩ when turned on, a characteristic called RDS(on). This number indicates the amount of power that is wasted, so the lower this number the better, as less power will be wasted thus increasing efficiency.
This power supply uses two electrolytic capacitors to filter the output from the active PFC circuit. The use of more than one capacitor here has absolute nothing to do with the “quality” of the power supply, as laypersons may assume (including people without the proper background in electronics doing power supply reviews around the web). Instead of using one big capacitor, manufacturers may choose to use two or more smaller components that will give the same total capacitance, in order to better accommodate space on the printed circuit board, as two or more capacitors with small capacitance are physically smaller than one capacitor with the same total capacitance. Silencer uses one 390 µF x 400 V and one 470 µF x 400 V capacitor connected in parallel; this is equivalent of one 860 µF x 400 V capacitor.
These capacitors are Japanese, from Chemi-Con and are labeled at 105° C. This is good for two reasons, first, Japanese capacitors do not leak; and second, usually manufacturers use 85° C capacitors here, so it is good to see a manufacturer using a capacitor with a higher temperature rating.
In the switching section, two IPW60R125CP power MOSFET transistors are used on the traditional two-transistor forward configuration. Each transistor supports up to 25 A at 25° C or 16 A at 100° C (note the difference temperature makes) or 82 A in pulse mode at 25° C, with a maximum RDS(on) of 125 mΩ.
This power supply uses a CM6802 active PFC/PWM combo controller.
Now let’s take a look at the secondary of this power supply.
This power supply uses eight SBR40S45CT Schottky rectifiers on its secondary and each one is capable of handling up to 40 A (20 A per internal diode at 110° C). All rectifiers are in charge of producing the +12 V output, with +5 V and +3.3 V being generated from the +12 V output using a DC-DC converter (i.e., a small switching power supply) located on a small printed circuit board. As mentioned this design is also used by other power supply series like TruePower New and Signature from Antec, M12D from Seasonic, UCP from Cooler Master and HX (750 W and above) from Corsair.
Three of the rectifiers are in charge of the direct rectification, while the remaining five are in charge of the “freewheeling” part of the rectification process (i.e., discharging the coil).
The maximum theoretical current each line can deliver is given by the formula I / (1 - D), where D is the duty cycle used and I is the maximum current supported by the rectifying diode. Just as an exercise, we can assume a typical duty cycle of 30%.
For our math we need to assume the path that has the lower limit, which is the direct rectification path. This would give us a maximum theoretical current of 171 A (40 A x 3 / 0.70). This maximum theoretical current limit is for the whole secondary, since +5 V and +3.3 V are also produced from the +12 V output. The practical limit will depend on other factors, but mainly on the coils used and on the design from the small DC-DC converter used to generate the +5 V and +3.3 V outputs. If this 171 A was solely pulled from the +12 V outputs, this would give us 2,052 W.
The DC-DC converter uses solid aluminum caps and two APW7073 controllers, one for each output, with seven APM2556N MOSFETs, which present a maximum RDS(on) of only 7.2 mΩ.
This power supply uses a PS223 monitoring integrated circuit, which is in charge of the power supply protections, like OCP (over current protection), over voltage protection (OVP), under voltage protection (UVP) and over temperature protection (OTP, not implemented on this unit).
Electrolytic capacitors from the secondary are also Japanese, from Chemi-Con and labeled at 105° C.
In Figure 17, you can see the power supply label containing all the power specs.
This power supply has a single rail design (a tradition with PC Power & Cooling), so there is not much to talk here. Keep in mind that the difference between a single-rail design and a multiple-rail design is how the over current protection (OCP) circuit is connected. On single-rail design there is only one OCP circuit monitoring all outputs, while on multiple-rail design there are several OCP circuits, each one monitoring a group of wires called “rails.”Now let’s see if this power supply can really deliver 910 W.
We conducted several tests with this power supply, as described in the article Hardware Secrets Power Supply Test Methodology.
First we tested this power supply with five different load patterns, trying to pull around 20%, 40%, 60%, 80%, and 100% of its labeled maximum capacity (actual percentage used listed under “% Max Load”), watching how the reviewed unit behaved under each load. In the table below we list the load patterns we used and the results for each load.
If you add all the power listed for each test, you may find a different value than what is posted under “Total” below. Since each output can vary slightly (e.g., the +5 V output working at +5.10 V), the actual total amount of power being delivered is slightly different than the calculated value. On the “Total” row we are using the real amount of power being delivered, as measured by our load tester.
The +12V1 and +12V2 inputs listed below are the two +12 V independent inputs from our load tester and during this test both were connected to the single rail provided by the reviewed unit.
7 A (84 W)
13 A (156 W)
20 A (240 W)
26 A (312 W)
33 A (396 W)
6 A (72 W)
12 A (144 W)
19 A (228 W)
26 A (312 W)
30.5 A (396 W)
2 A (10 W)
6 A (30 W)
8 A (40 W)
10 A (50 W)
15 A (75 W)
2 A (6.6 W)
6 A (19.8 W)
8 A (26.4 W)
10 A (33 W)
15 A (49.5 W)
1 A (5 W)
2 A (10 W)
2 A (10 W)
3 A (15 W)
3 A (15 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
0.5 A (6 W)
% Max Load
Ripple and Noise
Silencer 910 achieved an outstanding efficiency, especially for a 910 W product. If you pull up to 80% from its labeled capacity (i.e., up to 728 W) you will have an efficiency of at least 85%. WOW. At full load (910 W) efficiency was 83.4%, which isn’t bad at all!
Noise and ripple were very low during all tests, including -12 V (maximum of 35.6 mV) and +5VSB (maximum of 17.4 mV). Below you can see the results for test number five. As we always point out, the limits are 120 mV for +12 V and 50 mV for +5 V and +3.3 V and all numbers are peak-to-peak figures.
Below you can see the maximum we could pull from PC Power & Cooling Silencer 910. If we pulled one amp more the fuses from our load tester would blow. When we configured both +12 V inputs at 33 A the unit would shut down theses rails, indicating that some protection entered in action.
The idea behind of overload tests is to see if the power supply will burn/explode and see if the protections from the power supply are working correctly. This power supply didn’t burn or explode.
Silencer 910 could be easily labeled as a 1,000 W product. The manufacturer didn’t do this because otherwise they wouldn’t be able to get the 80 Plus Silver certification for this power supply.
32.9 A (394.8 W)
32.9 A (394.8 W)
25 A (125 W)
25 A (82.5 W)
3 A (15 W)
0.5 A (6 W)
% Max Load
PC Power & Cooling Silencer 910 power supply specs include:
PC Power & Cooling Silencer 910 is a terrific high-end power supply, presenting an outstanding efficiency of at least 85% if you pull up to 80% from its labeled capacity (i.e., up to 728 W). At full load (910 W) efficiency was 83.4%, which isn’t bad at all! Noise and ripple levels were always very low.
Notice that we are more rigorous on our tests than the folks at 80 Plus; they test power supplies at 23° C (a temperature impossible to be achieved inside a PC) while we test them at least double this temperature. Since efficiency drops with temperature, our results are lower (but more realistic) than those reported by 80 Plus.
This new trend of using a DC-DC converter design on the secondary is proving to be a winner for efficiency, as all power supplies we’ve reviewed using this kind of design achieved high efficiency in our tests.
Another highlight from this product is the number of SATA power connectors – twelve – more than enough even for the über nerd.
The only drawback we see on Silencer 910 is the lack of native support for SLI and CrossFire with three or more high-end video cards. If you want to run three or more high-end video cards at the same time with this power supply you will need to convert standard peripheral power plugs using adapters.
The price isn’t bad for a high-end 900 W power supply. It costs USD 10 more than Topower PowerBird 900 W, but presents a higher efficiency. On the other hand this model from Topower has a fully modular cabling system.
In summary, Silencer 910 is a very good option for the high-end user looking for a beefy power supply with very high efficiency and ultra low ripple and electrical noise levels.