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[nextpage title=”Introduction”]

Amacrox is a new player on the power supply market, with its products being manufactured by FSP. Will their Free Style 85PLUS 650 W (a.k.a. AX650-85EP) unit survive our tests?

Amacrox Free Style 85PLUS 650 WFigure 1: Amacrox Free Style 85PLUS 650 W power supply.

Amacrox Free Style 85PLUS 650 WFigure 2: Amacrox Free Style 85PLUS 650 W power supply.

Amacrox Free Style 85PLUS 650 W is 6 ½” (16.5 cm) deep, having a 120 mm fan on its bottom, active PFC and a modular cabling system, with some cables being permanently attached to the power supply – these cables use a nylon protection that comes from inside the unit. The cables included on Free Style 85PLUS 650 W are:

  • Main motherboard cable with a 20/24-pin connector (permanently attached to the power supply) (19 ¾” or 50 cm).
  • One cable with two ATX12V connectors that together form an EPS12V connector (permanently attached to the power supply) (21 ½” or 55 cm).
  • One cable with one six/eight-pin power connector for video cards (permanently attached to the power supply) (21 ½” or 55 cm).
  • One cable with one six/eight-pin power connector for video cards (modular cabling system) (17 ½” or 44.5 cm).
  • Two cables with four SATA power connectors each (modular cabling system) (17 ½” or 44.5 cm to the first connector, 5 7/8” or 15 cm between connectors).
  • Two cables with three standard peripheral power connectors each (modular cabling system) (17 ½” or 44.5 cm to the first connector, 5 7/8” or 15 cm between connectors).
  • Two adapters to convert any peripheral power connector into a floppy disk drive power connector.

The number of cables is adequate for a 650 W product, and having eight SATA power connectors is really good. All wires are 18 AWG, which is the correct gauge to be used.

Amacrox Free Style 85PLUS 650 WFigure 3: Cables.

Now let’s take an in-depth look inside this power supply.

[nextpage title=”A Look Inside The Free Style 85PLUS 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.

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.

Amacrox Free Style 85PLUS 650 WFigure 4: Overall look.

Amacrox Free Style 85PLUS 650 WFigure 5: Overall look.

Amacrox Free Style 85PLUS 650 WFigure 6: Overall look.

[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.

This power supply has two X capacitors and two Y capacitors more than the minimum required plus two X capacitors and one ferrite coil after the rectification bridge, but it doesn’t come with a MOV, which is a sin. This component is in charge of surge protection.

Amacrox Free Style 85PLUS 650 WFigure 7: Transient filtering stage (part 1).

Amacrox Free Style 85PLUS 650 WFigure 8: Transient filtering stage (part 2).

In the next page we will have a more detailed discussion about the components used in the Amacrox Free Style 85PLUS 650 W.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of Amacrox Free Style 85PLUS 650 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses two GBU606 rectifying bridges connected in parallel in its primary, each one being able to deliver up to 6 A at 100° C if a heatsink is used (which is the case) or up to 2.8 A at 100° C is a heatsink is not used. So in theory you would be able to pull up to 1,380 W from the power grid; assuming 80% efficiency, these bridges would allow this unit to deliver up to 1,104 W without burning themselves out. Talk about overspecification! Of course, we are only talking about these components, and the real limit will depend on all the other components in this power supply.

Amacrox Free Style 85PLUS 650 WFigure 9: Rectifying bridges.

Two FCPF21N60 power MOSFETs are used on the active PFC circuit, each one capable of delivering up to 20 A at 25° C or 12.5 A at 100° C in continuous mode (note the difference temperature makes) or up to 60 A at 25° C in pulse mode. These transistors present a maximum resistance of 150 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
.

Amacrox Free Style 85PLUS 650 WFigure 10: Active PFC transistors and diode.

The electrolytic capacitor in charge of filtering the active PFC output is Japanese from Hitachi and labeled at 105° C, which is great.

In the switching section, two SPA20N60C3 power MOSFET transistors are used, each one capable of delivering up to 20.7 A at 25° C or 13.1 A at 100° C in continuous mode, or up to 62.1 A in pulse mode at 25° C, with an RDS(on) of 190 mΩ.

Amacrox Free Style 85PLUS 650 WFigure 11: Switching transistors.

This power supply uses the omnipresent CM6800 PFC/PWM combo controller.

Amacrox Free Style 85PLUS 650 WFigure 12: PFC/PWM controller.

Now let’s take a look at the secondary of this power supply.

[nextpage title=”Secondary Analysis”]

Amacrox Free Style 85PLUS 650 W uses eight Schottky rectifiers on the secondary.

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%.

The +12 V output is produced by four SBR40U60CT Schottky rectifiers (40 A, 20 A per internal diode at 100° C, 0.60 V maximum voltage drop) connected in parallel, giving us a maximum theoretical current of 114 A or 1,371 W for the +12 V output. Talk about overspecification!

The +5 V output is produced by two SBR30U30CT Schottky rectifiers (30 A, 15 A per internal diode at 140° C, maximum forward voltage of 0.54 V) connected in parallel. This gives us a maximum theoretical current of 43 A or 214 W for the +5 V output.

The +3.3 V output is produced by another two SBR30U30CT Schottky rectifiers, giving us a maximum theoretical current of 43 A or 141 W for the +3.3 V output.

Amacrox Free Style 85PLUS 650 WFigure 13: Rectifiers.

The secondary is monitored by two integrated circuits, a PS223, which supports OCP (over current protection), OVP (over voltage protection), UVP (under voltage protection) and OTP (over temperature protection, not implemented on this power supply), and a WT7518, which provides four individual over current sensors.

Amacrox Free Style 85PLUS 650 WFigure 14: Monitoring circuit.

Electrolytic capacitors from the secondary are from Teapo and labeled at 105° C, as usual.

[nextpage title=”Power Distribution”]

In Figure 15, you can see the power supply label containing all the power specs.

Amacrox Free Style 85PLUS 650 WFigure 15: Power supply label.

This power supply has four virtual rails, distributed like this:

  • +12V1 (yellow wire with white stripe): Video card power cable that is permanently attached to the power supply.
  • +12V2 (yellow wire with blue stripe): ATX12V/EPS12V connectors.
  • +12V3 (solid yellow wire): Main motherboard cable, peripheral and SATA power connectors.
  • +12V4 (yellow wire with black stripe): Video card power connectors from modular cabling system.

This distribution is perfect, as it separates the CPU (ATX12V/EPS12V), the video card and all the rest on different rails.

Now let’s see if this power supply can really deliver 650 W.– page break —

[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 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 all tests the +12V1 input was connected to the power supply +12V1 and +12V3 rails while the +12V2 input was connected to the power supply +12V2 rail.

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12V1 5 A (60 W) 10 A (120 W) 15 A (180 W) 20 A (240 W) 29 A (348 W)
+12V2 5 A (60 W) 10 A (120 W) 14 A (168 W) 19 A (228 W) 19 A (228 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 137.9 W 263.9 W 388.1 W 521.8 W 643.4 W
% Max Load 21.2% 40.6% 59.7% 80.3% 99.0%
Room Temp. 45.8° C 46.7° C 45.2° C 47.7° C 48.9° C
PSU Temp. 47.2° C 47.7&de
g; C
48.0° C 49.5° C 50.0° C
Voltage Stability Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Pass
AC Power 163.7 W 307.4 W 454.6 W 622.0 W 785.0 W
Efficiency 84.2% 85.8% 85.4% 83.9% 82.0%
AC Voltage 114.2 V 113.1 V 111.7 V 109.9 V 107.9 V
Power Factor 0.980 0.992 0.996 0.997 0.998
Final Result Pass Pass Pass Pass Pass

The reviewed power supply can really deliver 650 W at 49° C.

During our tests four and five over current protection (OCP) kicked in when we tried to pull more than 19 A from +12V2 (which is good), so we compensated this by pulling more from the +12V1 input from our load tester (which was connected to the power supply +12V1 and +12V3 rails).

Efficiency was terrific for a product that is going to be introduced on the market for less than USD 85, above 85% when we pulled between 40% and 60% from the labeled wattage (between 260 W and 390 W). When we pulled 20% of the maximum load (130 W) and 80% of the maximum load (520 W) efficiency was still high at 84%. And at full load efficiency was at 82%, perfectly matching its 80 Plus Bronze certification at high temperatures, something not all 80 Plus Bronze-certified power supplies are able to do.

Voltage was within the allowed range and noise and ripple were way below the maximum allowed. At full load noise level at +12V1 input from our load tester was at 35.6 mV, at +12V2 it was at 40.4 mV, at +5 V it was at 32.6 mV and at +3.3 V it was at 27.6 mV. The maximum allowed is 120 mV for the +12 V outputs and 50 mV for the +5 V and +3.3 V outputs. All values are peak-to-peak.

Let’s see if we could pull more than 650 W from the reviewed unit.

[nextpage title=”Overload Tests”]

We had already discovered that the over current protection was set at 20 A (see previous page). The maximum we could pull from this unit is listed below, and if we tried to pull more than that the unit would shut down. It is important to note that we were limited by our equipment, since we couldn’t pull more than 19 A from +12V2 because otherwise OCP would kick in and we couldn’t pull more than 33 A from +12V1 input (which was connected to the power supply +12V1 and +12V3 rails) because this is the maximum our load tester can deliver.

Input Maximum
+12V1 33 A (396 W)
+12V2 19 A (228 W)
+5V 22 A (110 W)
+3.3 V 22 A (72.6 W)
+5VSB 2.5 A (30 W)
-12 V 0.5 A (6 W)
Total 813.3 W
% Max Load 125.1%
Room Temp. 46.5° C
PSU Temp. 48.7° C
AC Power 1,032 W
Efficiency 78.8%
AC Voltage 105.1 V
Power Factor 0.999

[nextpage title=”Main Specifications”]

Amacrox Free Style 85PLUS 650 W power supply specs include:

  • ATX12V 2.2
  • EPS12V 2.91
  • Nominal labeled power: 650 W.
  • Measured maximum power: 813.3 W at 46.5° C.
  • Labeled efficiency: 85% minimum, 80 Plus Bronze certified
  • Measured efficiency: Between 82.0% and 85.8% at 115 V (nominal, see complete results for actual voltage).
  • Active PFC: Yes.
  • Modular Cabling System: Yes.
  • Motherboard Power Connectors: One 20/24-pin connector and two ATX12V connectors that together form an EPS12V connector (permanently attached to the power supply).
  • Video Card Power Connectors: One six/eight-pin connector in one cable permanently attached to the power supply and one six/eight pin connector in one cable on the modular cabling system.
  • SATA Power Connectors: Eight in two cables.
  • Peripheral Power Connectors: Six in two cables.
  • Floppy Disk Drive Power Connectors: Two, if the included adapters are used.
  • Protections: Over current (tested and working), over voltage (OVP, not tested) and short-circuit (SCP, tested and working) protections.
  • Warranty: N/A.
  • Real Manufacturer: FSP
  • More Information: https://www.amacrox.com
  • Suggested Price: USD 84.90

[nextpage title=”Conclusions”]

We were really impressed by Amacrox Free Style 85PLUS 650 W: it is an inexpensive yet high-performing power supply. Efficiency was at least at 84% when we pulled up to 80% from its labeled capacity (520 W) and at 82% when it was delivering its full power.

We could easily pull up to 810 W from it at high temperatures, thanks to its highly overspec’ed components – which is always great to see. Of course during this extreme configuration efficiency dropped below the 80% mark.

Voltages were always inside the allowed range and noise and ripple were very low.

Amacrox power supplies are currently being sold mainly in Asia and we anxiously hope they can make their way to America, because it brings a terrific cost/benefit ratio for the average user.