PC Power & Cooling Silencer Mk II 650 W Power Supply Review

[nextpage title=”Introduction”]

The new Silencer Mk II power supply series from PC Power & Cooling features a synchronous design with DC-DC conversion, single +12 V rail, 80 Plus Silver certification, and seven-year warranty. We’ve already tested the 750 W version and it proved to be an excellent product. Let’s see if the 650 W model is also a good option.

The power supplies from Silencer Mk II series are manufactured by Highpower.

Figure 1: PC Power & Cooling Silencer Mk II 650 W power supply

Figure 2: PC Power & Cooling Silencer Mk II 650 W power supply

The PC Power & Cooling Silencer Mk II 650 W is 6.3” (160 mm) deep, using a 135 mm fan on its bottom. This fan is a Globe Fan RL4Z-B1352512H, which is a ball-bearing fan with a maximum rotation of 1,500 rpm and a maximum airflow of 106.86 cfm.

This unit features active PFC, of course, and following PC Power & Cooling tradition, it doesn’t come with a modular cabling system. In fact, OCZ, the owner of PC Power & Cooling, decided to keep units with a single +12 V rail and no modular cabling system under PC Power & Cooling brand, while selling power supplies with modular cabling systems and multiple +12 V rails under their own brand. The cables included are the following:

• Main motherboard cable with a 20/24-pin connector, 19.3” (49 cm) long
• One cable with one ATX12V connector, 23.2” (59 cm) long
• One cable with one EPS12V connector, 23.2” (59 cm) long
• One cable with one six/eight-pin connector for video cards, 23.2” (59 cm) long
• One cable with one six-pin connector for video cards, 23.2” (59 cm) long
• Two cables, each with four SATA power connectors, 15.7” (40 cm) to the first connector, 5.5” (14 cm) between connectors
• Two cables, each with three standard peripheral power connectors and one floppy disk drive power connector, 23.2” (59 cm) to the first connector, 5.1” (13 cm) between connectors

All wires are 18 AWG, except the orange (+3.3 V) wires in the main motherboard cable, which are thicker (16 AWG).

The cable configuration is satisfactory for a 650 W power supply, however it would be nice if the manufacturer had added two more video card power connectors in order to allow you to install two video cards that require two auxiliary power connectors each.

Figure 3: Cables

Let’s now take an in-depth look inside this power supply.

[nextpage title=”A Look Inside The PC Power & Cooling Silencer Mk II 650 W”]

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.

On this page we will have an overall look, and then in the following pages we will discuss in detail the quality and ratings of the components used. The printed circuit board of the Mk II 650 W is identical to the one used in the 750 W model, so we were curious to see what components were changed.

Figure 4: Top view

Figure 5: Front quarter view

Figure 6: Rear quarter view

[nextpage title=”Transient Filtering Stage”]

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. 

In this power supply, this stage is flawless. It has one X capacitor and two Y capacitors more than the minimum required, plus one X capacitor after the rectifying bridge.

Figure 7: Transient filtering stage (part 1)

Figure 8: Transient filtering stage (part 2)

In the next page we will have a more detailed discussion about the components used in the PC Power & Cooling Silencer Mk II 650 W.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of the PC Power & Cooling Silencer Mk II 650 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBJ2506 rectifying bridge on its primary, but unfortunately it isn’t attached to a heatsink. This component supports up to 25 A at 100° C, so in theory, you would be able to pull up to 2,875 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 2,300 W without burning itself out. Of course, we are only talking about this component, and the real l
imit will depend on all the other components in this power supply. The 750 W model uses two 15 A bridges connected in parallel here.

Figure 9: Rectifying bridge

The active PFC circuit uses two SPW20N60C3 MOSFETs, each one capable of delivering up to 20.7 A at 25° C or up to 13.1 A at 100° C (note the difference temperature makes) in continuous mode, or up to 62.1 A in pulse mode at 25° C. These transistors present a 190 mΩ resistance when turned on, a characteristic called RDS(on). The lower this number the better, meaning that the transistors will waste less power and the power supply will have a higher efficiency. The 750 W model uses more powerful transistors here.

Figure 10: Active PFC transistors

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 capacitors with the same total capacitance are physically smaller than a single capacitor with equivalent capacitance. The Silencer Mk II 650 W uses two 330 µF x 400 V capacitors connected in parallel, the equivalent of one 660 µF x 400 V capacitor. They are manufactured by Rubycon, a Japanese company, and labeled at 105° C.

In the switching section, two IPP60R190C6 power MOSFETs are used in the traditional two-transistor forward configuration. They are capable of handling up to 20.2 A at 25° C or up to 12.8 A at 100° C in continuous mode, or up to 59 A at 25° C in pulse mode, with an RDS(on) of 190 mΩ. The 750 W model uses more powerful transistors here.

Figure 11: Active PFC diode and one of the switching transistors

The primary is controlled by the omnipresent CM6800 active PFC/PWM combo.

Figure 12: Active PFC/PWM combo controller

Let’s now take a look at the secondary of this power supply.

[nextpage title=”Secondary Analysis”]

This power supply uses a synchronous design on its secondary, meaning that the Schottky rectifiers were replaced by MOSFET transistors in order to increase efficiency. On top of that, this unit uses a DC-DC design, meaning that this unit is basically a +12 V power supply, with the +5 V and +3.3 V outputs being generated by two small power supplies attached to the +12 V output.

The +12 V output is generated by two AOT480 MOSFETs, each one capable of handling up to 180 A at 25° C or up to 134 A at 100° C in continuous mode, or up to 500 A at 25° C in continuous mode, with an RDS(on) of only 4.5 mΩ. The +12 V output is also used to generate the +5 V and +3.3 V outputs, but just as an exercise, if we pulled all power from the +12 V output this unit would have a maximum theoretical current at 100° C of 191 A or 2,297 W. The 750 W model uses one additional transistor here.

Figure 13: Transistors of the +12 V rail

The +5 V and +3.3 V outputs are generated by two small power supplies available on small daughterboards attached to the +12 V rail. Each of these power supplies is comprised of four IPD060N03L MOSFETs (50 A at 100° C, 6 mΩ resistance) and one APW7073 PWM controller.

Figure 14: One of the DC-DC converters

This power supply uses a PS224 monitoring integrated circuit, which supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections. The over current protection circuit available in this integrated circuit has four channels, one for +3.3 V, one for +5 V, and two for +12 V. However, in this power supply only one +12 V OCP channel is used, as it has a single-rail design.

Figure 15: Monitoring circuit

The electrolytic capacitors available in the secondary are from also Japanese, from Chemi-Con, and labeled at 105° C. The secondary also has some solid capacitors.

One curious thing we noticed was the adaptation the manufacturer did to add an extra electrolytic capacitor to the +12 V rail (see in Figure 16). This adaptation is also present in the 750 W model from this series.

Figure 16: Additional electrolytic capacitor for the +12 V rail

[
nextpage title=”Power Distribution”]

In Figure 17, you can see the power supply label containing all the power specs.

Figure 17: Power supply label

This power supply has a single +12 V rail, so there is not much to talk about here.

Let’s now see if this power supply can really deliver 650 W.

[nextpage title=”Load Tests”]

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 the behavior of the reviewed unit 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 powers listed for each test, you may find a different value than what is posted under “Total” below. Since each output can have a slight variation (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. In the “Total” row, we are using the real amount of power being delivered, as measured by our load tester.

The +12VA and +12VB inputs listed below are the two +12 V independent inputs from our load tester. During this test both were connected to the power supply single +12 V rail (the EPS12V connector was installed on the +12VB input).

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	5 A (60 W)	10 A (120 W)	15 A (180 W)	20 A (240 W)	23.75 A (285 W)
+12VB	5 A (60 W)	10 A (120 W)	14 A (168 W)	20 A (240 W)	23.75 A (285 W)
+5V	1 A (5 W)	2 A (10 W)	4 A (20 W)	6 A (30 W)	8 A (40 W)
+3.3 V	1 A (3.3 W)	2 A (6.6 W)	4 A (13.2 W)	6 A (19.8 W)	8 A (26.4 W)
+5VSB	1 A (5 W)	1 A (5 W)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)
-12 V	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)
Total	140.5 W	268.6 W	391.8 W	536.8 W	648.4 W
% Max Load	21.6%	41.3%	60.3%	82.6%	99.8%
Room Temp.	45.2° C	44.1° C	45.1° C	45.5° C	48.8° C
PSU Temp.	44.9° C	45.2° C	45.6° C	48.0° C	49.0° C
Voltage Stability	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Fail on -12 V	Fail on -12 V	Fail on -12 V	Fail on -12 V
AC Power	164.7 W	307.5 W	450.4 W	627.0 W	776.0 W
Efficiency	85.3%	87.3%	87.0%	85.6%	83.6%
AC Voltage	109.5 V	108.6 V	106.6 V	107.0 V	104.8 V
Power Factor	0.947	0.975	0.986	0.991	0.993
Final Result	Pass	Pass	Pass	Pass	Pass

The PC Power & Cooling Silencer Mk II 650 W can really deliver its labeled wattage at high temperatures.

Efficiency was high, between 83.6% and 87.3%. Efficiency at full load was a little bit below what is required by the 80 Plus Silver certification (85%), but as we always explain, tests performed by 80 Plus are done at a room temperature of only 23° C, while this particular power supply we tested at almost 50° C at full load, and efficiency drops with temperature.

Voltages were always inside the allowed range.

Noise and ripple were always at good levels, even though we’d like to see even lower levels at +12 V. At -12 V, however, noise was above the maximum allowed from test two on, peaking 172.8 mV during test five. We’ve also seen high noise levels at this output with the 750 W model from this series. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for +12 V and -12 V, and 50 mV for +5 V and +3.3 V. All values are peak-to-peak figures.

Figure 18: +12VA input from load tester during test five at 648.4 W (81.8 mV)

Figure 19: +12VB input from load tester during test five at 648.4 W (73.3 mV)

Figure 20: +5V rail during test five at 648.4 W (16.6 mV)

Figure 21: +3.3 V rail during test five at 648.4 W (25.8 mV)

Let’s see if we can pull even more from the PC Power & Cooling Silencer Mk II 650 W.

[nextpage title=”Overload Tests”]

Below you can see the maximum we could pull from this power supply. If we tried to increase one amp at any given output, the unit would shut down, showing that one of its protections kicked in, which is always the desired behavior. During this test, the noise level at -12 V output was at 223.4 mV and the +3.3 V output was below the minimum allowed, at +3.04 V. The other outputs were still inside specs. Interesting enough the maximum amount of power we could pull from this unit matches precisely the peak wattage advertised by the manufacturer (780 W).

Input	Overload Test
+12VA	30 A (360 W)
+12VB	30 A (360 W)
+5V	10 A (50 W)
+3.3 V	10 A (33 W)
+5VSB	1 A (5 W)
-12 V	0.5 A (6 W)
Total	797.4 W
% Max Load	122.7%
Room Temp.	45.4° C
PSU Temp.	44.6° C
AC Power	990 W
Efficiency	80.5%
AC Voltage	101.4 V
Power Factor	0.996

[nextpage title=”Main Specifications”]

The specs of the PC Power & Cooling Silencer Mk II 650 W include:

• Nominal labeled power: 650 W continuous at 50° C, 780 W peak
• Measured maximum power: 797.4 W at 45.4° C ambient
• Labeled efficiency: up to 88%, 80 Plus Silver certification
• Measured efficiency: Between 83.6% and 87.3% at 115 V (nominal, see complete results for actual voltage)
• Active PFC: Yes
• Modular Cabling System: No
• Motherboard Power Connectors: One 20/24-pin connector, one ATX12 V connector, and one EPS12V connector
• Video Card Power Connectors: Two, one six-pin and one six/eight-pin on separate cables
• SATA Power Connectors: Eight on two cables
• Peripheral Power Connectors: Six on two cables
• Floppy Disk Drive Power Connectors: Two on two cables
• Protections: Over voltage (OVP) and over current (OCP). Although not listed by the manufacturer, this unit also has under voltage (UVP) and short-circuit (SCP) protections
• Warranty: Seven years
• Real Manufacturer: Highpower
• More Information: https://www.pcpower.com
• Average price in the US*: USD 118.00

* Researched at Amazon.com on the day we published this review.

[nextpage title=”Conclusions”]

The new PC Power & Cooling Silencer Mk II 650 W is a very good power supply, presenting better performance than practically all 650 W power supplies we’ve reviewed to date. It only loses to Seasonic X-Series 650 W, but this model with 80 Plus Gold certification is more expensive.

The only flaw of the Mk II 650 W is the high noise level at the -12 V output, a problem that won’t affect most users, since this rail is only used by some add-on audio cards. This problem, however, must be noted and that is the only reason we are giving this unit our Silver Award instead of our Golden Award.

Also, it would be nice if this unit had four video card power connectors instead of only two.