Introduction

The new FORTRESS power supply series from Rosewill has 450 W, 550 W, 650 W, and 750 W versions, all with the 80 Plus Platinum certification. Let’s see if the 650 W model is a good product.

The FORTRESS power supplies are manufactured by ATNG, and the FORTRESS-650 is a rebranded ATNG ATM-650SERIES-P.

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Figure 1: Rosewill FORTRESS-650 power supply

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Figure 2: Rosewill FORTRESS-650 power supply

The Rosewill FORTRESS-650 is 6.5” (165 mm) deep, using a 135 mm ball bearing fan on its bottom (Rosewill RL4ZB1352512M, which is actually manufactured by Globe Fan). 

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Figure 3: Fan

The reviewed power supply doesn’t have a modular cabling system. All cables are protected with nylon sleeves that come from inside the unit. This power supply comes with the following cables:

• Main motherboard cable with a 20/24-pin connector, 21.3” (54 cm) long
• One cable with two ATX12V connectors that together form an EPS12V connector, 25.2” (64 cm) long
• Two cables, each with two six/eight-pin connectors for video cards, 23.6” (60 cm) to the first connector, 5.9” (15 cm) between connectors
• Two cables, each with four SATA power connectors, 19.7” (50 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with three standard peripheral power connectors, 19.7” (50 cm) to the first connector, 5.9” (15 cm) between connectors
• One cable with two standard peripheral power connectors and one floppy disk drive power connector, 19.7” (50 cm) to the first connector, 5.9” (15 cm) between connectors

The main motherboard cable, the EPS12V/ATX12V cable, and the video card cables use thicker 16 AWG wires, while the peripheral and SATA power cables use 18 AWG wires, which is the minimum recommended gauge.

The cable configuration is excellent for a 650 W model, with eight SATA power connectors and four video card power connectors, allowing you to install two high-end video cards out of the box.

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Figure 4: Cables

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

A Look Inside the Rosewill FORTRESS-650

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.

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Figure 5: Top view

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Figure 6: Front quarter view

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Figure 7: Rear quarter view

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Figure 8: The printed circuit board

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 the transient filtering stage, this power supply is flawless, with two X capacitors and two Y capacitors more than the minimum required, and with two additional Y capacitors and one additional X capacitor after the rectifying bridge.

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Figure 9: Transient filtering stage (part 1)

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Figure 10: Transient filtering stage (part 2)

On the next page, we will have a more detailed discussion about the components used in the Rosewill FORTRESS-650.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the Rosewill FORTRESS-650. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.

This power supply uses one U15K80R rectifying bridge, which is attached to the same heatsink as the active PFC and switch transistors. Unfortunately, we couldn’t find the datasheet for this component, but we know it supports up to 15 A. So, in theory, you would be able to pull up to 1,725 W from a 115 V power grid. Assuming 80% efficiency, the bridge would allow this unit to deliver up to 1,380 W without burning itself out (or 1,553 W at 90% efficiency). Of course, we are only talking about this particular component. The real limit will depend on all the components combined in this power supply.

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Figure 11: Rectifying bridge

The active PFC circuit uses an IPW60R099C6 MOSFET, which supports up to 37.9 A at 25° C or 24 A at 100° C in continuous mode (see the difference temperature makes) or 112 A at 25° C in pulse mode. This transistor presents a maximum 99 mΩ resistance when turned on, a characteristic called RDS(on). The lower the number the better, meaning that the transistor will waste less power, and the power supply will have a higher efficiency.

The active PFC circuit is controlled by a CM6502S integrated circuit.

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Figure 12: Active PFC controller

The output of the active PFC circuit is filtered by one 390 µF x 400 V Japanese electrolytic capacitor, from Chemi-Con, labeled at 105° C.

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Figure 13:  Capacitor

In the switching section, two IPW50R140CP MOSFETs are employed using a resonant configuration. Each of these transistors supports up to 23 A at 25° C or 15 A at 100° C in continuous mode or up to 56 A at 25° C in pulse mode, with a maximum RDS(on) of 140 mΩ.

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Figure 14: One of the switching transistors, the active PFC diode, and the active PFC transistor

The switching transistors are controlled by a CM6901 integrated circuit.

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Figure 15: Resonant controller

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

Secondary Analysis

The Rosewill FORTRESS-650 uses a synchronous design, meaning that the rectifiers were replaced with MOSFETs. Also, this power supply uses a DC-DC design, meaning that it is basically a +12 V power supply, with the +5 V and +3.3 V outputs being generated through two smaller switching power supplies connected to the +12 V rail. Both designs are used to increase efficiency.

The +12 V output uses four IPP023N04N G MOSFETs, each supporting up to 90 A at 100° C in continuous mode or 400 A at 25° C in pulse mode, with a maximum RDS(on) of 2.3 mΩ.

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Figure 16: Two of the four +12 V rectifiers and the +5VSB rectifier

As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters. Both are located on the same daughterboard, and each is managed by a CAT7523 PWM controller and uses a pair of MOSFETs. Unfortunately, the manufacturer scraped off the markings of these transistors, so we couldn’t identify the exact models.

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Figure 17: The DC-DC converters

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Figure 18: The DC-DC converters

This power supply uses a GR8313 monitoring integrated circuit, which only supports over voltage (OVP) and under voltage (UVP) protections.

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Figure 19: Monitoring circuit

The electrolytic capacitors that filter the outputs are Japanese, from Chemi-Con, and labeled at 105° C, as usual. This power supply also makes use of solid capacitors. See Figure 20.

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Figure 20: Secondary capacitors

Power Distribution

In Figure 21, you can see the power supply label containing all the power specs.

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Figure 21: Power supply label

As you can see, this power supply has a single +12 V rail, so there is not much to talk about here.

How much power can this unit really deliver? Let’s find out.

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, the +12VA input was connected to the power supply +12V1 and +12V3 rails, while the +12VB input was connected to the power supply +12V2 rail.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	5 A (60 W)	10 A (120 W)	14.5 A (174 W)	19 A (228 W)	23.5 A (282 W)
+12VB	5 A (60 W)	10 A (120 W)	14 A (168 W)	19 A (228 W)	23.5 A (282 W)
+5 V	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)	1.5 A (7.5 W)	2 A (10 W)	2.5 A (12.5 W)	3 A (15 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	140.0 W	271.4 W	392.4 W	525.4 W	650.4 W
% Max Load	21.5%	41.8%	60.4%	80.8%	100.1%
Room Temp.	45.2° C	46.1° C	45.8° C	47.1° C	48.8° C
PSU Temp.	48.8° C	49.8° C	49.3° C	49.6° C	50.4° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	152.6 W	294.7 W	431.0 W	584.8 W	741.0 W
Efficiency	91.7%	92.1%	91.0%	89.8%	87.8%
AC Voltage	115.2 V	112.1 V	110.3 V	108.9 V	107.9 V
Power Factor	0.978	0.982	0.989	0.994	0.995
Final Result	Pass	Pass	Pass	Pass	Pass

The 80 Plus Platinum certification guarantees minimum efficiencies of 90% at 20% load, 92% at 50% load, and 89% at 100% load. In our tests, the Rosewill FORTRESS-650 presented 91.7% efficiency at 20% load, matching the 80 Plus Platinum certification. We didn’t test this power supply at 50% load, but considering that we saw 92.1% efficiency at 40% load, we can assume that this unit is able to achieve 92% efficiency at 50% load. At full load, we saw 87.8% efficiency, which is below the minimum advertised by the 80 Plus Platinum certification. However, we have to consider that during this test, the AC voltage dropped to 108 V, which is probably the culprit. Also, always keep in mind that we test power supplies between 45° C and 50° C, while the 80 Plus tests are conducted at 23° C, and efficiency drops with temperature.

Voltage regulation was very good, with all positive voltages closer to their nominal values (3% regulation) during the first four tests. The -12 V output was not inside this tighter range, but was still inside the allowed zone. The ATX12V specification states that positive voltages must be within 5% of their nominal values, and negative voltages must be within 10% of their nominal values.

Let’s discuss the ripple and noise levels on the next page.

Ripple and Noise Tests

Voltages at the power supply outputs must be as “clean” as possible, with no noise or oscillation (also known as “ripple”). The maximum ripple and noise levels allowed are 120 mV for +12 V and -12 V outputs, and 50 mV for +5 V, +3.3 V and +5VSB outputs. All values are peak-to-peak figures. We consider a power supply as being top-notch if it can produce half or less of the maximum allowed ripple and noise levels.

The Rosewill FORTRESS-650 provided low ripple and noise levels.

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	21.2 mV	25.6 mV	35.8 mV	34.6 mV	41.8 mV
+12VB	22.6 mV	26.4 mV	39.2 mV	39.4 mV	44.6 mV
+5 V	14.2 mV	13.4 mV	14.6 mV	20.4 mV	26.8 mV
+3.3 V	11.2 mV	13.2 mV	17.4 mV	20.8 mV	29.6 mV
+5VSB	10.8 mV	13.2 mV	17.4 mV	24.0 mV	37.4 mV
-12 V	24.2 mV	39.6 mV	54.0 mV	41.8 mV	44.8 mV

Below you can see the waveforms of the outputs during test five.

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Figure 22: +12VA input from load tester during test five at 650.4 W (41.8 mV)

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Figure 23: +12VB input from load tester during test five at 650.4 W (44.6 mV)

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Figure 24: +5V rail during test five at 650.4 W (26.8 mV)

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Figure 25: +3.3 V rail during test five at 650.4 W (29.6 mV)

Overload Tests

Below you can see the maximum we could pull from this power supply. The objective of this test is to see if the power supply has its protection circuits working properly. This unit passed this test, since it shut down when we tried to pull more than what is listed below. During this test, noise levels at +3.3 V and +5VSB were above the maximum allowed, at 57.4 mV and 63.4 mV, respectively. The +3.3 V output was outside the tighter 3% regulation we always want to see, at +3.19 V, but still inside the allowed range.

Input	Overload Test
+12VA	30 A (360 W)
+12VB	30 A (360 W)
+5 V	12 A (60 W)
+3.3 V	12 A (39.6 W)
+5VSB	3 A (15 W)
-12 V	0.5 A (6 W)
Total	837.4 W
% Max Load	128.8%
Room Temp.	44.8° C
PSU Temp.	52.2° C
AC Power	1,008 W
Efficiency	83.1%
AC Voltage	106.3 V
Power Factor	0.997

Main Specifications

The main specifications for the Rosewill FORTRESS-650 power supply include:

• Standards: ATX12V 2.31 and EPS12V 2.92
• Nominal labeled power: 650 W at 50° C
• Measured maximum power: 837.4 W at 44.8° C
• Labeled efficiency: Between 89% and 94%, 80% Plus Platinum certification, 90% minimum at light (i.e., 20%) load, 92% minimum at typical (i.e., 50%) load, and 89% minimum at full load
• Measured efficiency: Between 87.8% and 92.1%, 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 and two ATX12V connectors that together form an EPS12V connector
• Video Card Power Connectors: Four six/eight-pin connectors on two cables
• SATA Power Connectors: Eight on two cables
• Peripheral Power Connectors: Five on two cables
• Floppy Disk Drive Power Connectors: One
• Protections (as listed by the manufacturer): NA
• Are the above protections really available? This power supply has over voltage (OVP), under voltage (UVP), and short-circuit (SCP) protections
• Warranty: Seven years
• Real Model: ATNG ATM-650SERIES-P
• More Information: http://www.rosewill.com
• MSRP in the U.S.: USD 160.00

Conclusions

On our tests, the Rosewill FORTRESS-650 presented efficiency between 87.8% and 92.1%, low ripple and noise levels, and positive voltages within 3% of their nominal values. The cable configuration is adequate for a high-end 650 W unit.

This power supply will arrive on the market with a suggested price of USD 160. Since the 750 W version of this power supply costs USD 140 today, this means Newegg.com will offer the reviewed unit for less than USD 140, probably USD 120 or USD 130, which is not bad at all for a 650 W power supply with the 80 Plus Platinum certification. The main competitor for the FORTRESS-650 is the Antec EarthWatts Platinum 650 W, which today costs USD 120 at Newegg.com, providing a terrific price/performance ratio. But, if you are the kind of user who prefers to pay a little more to have higher quality components, the FORTRESS-650 is a better choice, as it uses Japanese capacitors labeled at 105° C as well as solid capacitors, which doesn’t happen with its competitor from Antec.