OCZ ModXStream Pro 600 W Power Supply Review

[nextpage title=”Introduction”]

ModXStream Pro is a power supply series from OCZ featuring a modular cabling system and a very attractive price tag, at this moment featuring 500 W, 600 W and 700 W models, with the manufacturer promising that these units can deliver their labeled wattage at 40° C. Let’s see if the 600 W version is a good pick.

This power supply is manufactured by Highpower.

Figure 1: OCZ ModXStream Pro 600 W power supply.

Figure 2: OCZ ModXStream Pro 600 W power supply.

OCZ ModXStream Pro 600 W is 6 ¼” (160 mm) deep, using a 135 mm fan on its bottom and featuring active PFC circuit, of course.

The modular cabling system present on the 600 W model has six connectors, two red for the video card cables and four black for the SATA and peripheral power cables. The main motherboard cable, one ATX12V cable and one EPS12V cable are permanently attached to the power supply. They all have a nylon protection that comes from inside the unit. The cables included are:

• Main motherboard cable with a 20/24-pin connector, 17 ¾” (45 cm) long (permanently attached to the power supply).
• One cable with one ATX12V connector, 18 1/8” (46 cm) long (permanently attached to the power supply).
• One cable with one EPS12V connector, 18 1/8” (46 cm) long (permanently attached to the power supply).
• One cable with one six-pin connector for video cards, 18 1/8” (46 cm) long.
• One cable with one six/eight-pin connector for video cards, 18 1/8” (46 cm) long.
• Two cables with three SATA power connectors each, 18 1/8” (46 cm) to the first connector, 6 ¼” (160 mm) between connectors.
• Two cables with two standard peripheral power connectors and one floppy disk drive power connector, 18 1/8” (46 cm) to the first connector, 5 7/8” (15 cm) between connectors.

This configuration is satisfactory for a 600 W product.

All cables use 18 AWG wires, which is the minimum recommended, except the +3.3 V (orange) wires from the main motherboard cable, which are thicker (16 AWG).

Figure 3: Cables.

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

[nextpage title=”A Look Inside The OCZ ModXStream Pro 600 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.

Figure 4: Overall look.

Figure 5: Overall look.

Figure 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 is flawless on this stage, with two Y capacitors and one X capacitor more than the minimum required, plus an 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 OCZ ModXStream Pro 600 W.

[nextpage title=”Primary Analysis”]

On this page we will take an in-depth look at the primary stage of OCZ ModXStream Pro 600 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one GBU1005 rectifying bridge, which supports up to 10 A at 100° C if a heatsink is used, which is the case. At 115 V this unit would be able to pull up to 1,150 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 920 W without burning itself out. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Figure 9: Rectifying bridge.

Two SPW20N60C3 power MOSFETs are used on the active PFC circuit, each one 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 up to 62.1 A at 25
° C in pulse mode. 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.

Figure 10: Active PFC transistors and diode.

The electrolytic capacitor used to filter the output from the active PFC circuit is from Teapo and labeled at 85° C.

The reviewed power supply uses two STP25NM60N power MOSFET transistors on its switching section, installed on the traditional two-transistor forward configuration. Each transistor can handle up to 21 A at 25° C or up to 13 A at 100° C in continuous mode, or up to 84 A at 25° C in pulse mode, with a maximum RDS(on) of 160 mΩ.

Figure 11: Switching transistors.

The primary is controlled by a FAN4800 PFC/PWM combo controller.

Figure 12: PFC/PWM combo controller.

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

[nextpage title=”Secondary Analysis”]

This power supply has six Schottky rectifiers on its secondary, plus a diode in charge of the +5VSB output rectification.

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 two KCQ60A06 Schottky rectifiers connected in parallel, each one supporting up to 60 A (30 A per internal diode at 69° C, 0.67 V maximum voltage drop). This gives us a maximum theoretical current of 43 A or 514 W for the +12 V output.

The +5 V output is produced by two ESAD83-004 Schottky rectifiers connected in parallel, each one capable of delivering up to 30 A (15 A per internal diode at 90° C, 0.55 V maximum voltage drop), giving 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 ESAD83-004 Schottky rectifiers, giving us a maximum theoretical current of 43 A or 141 W for the +3.3 V output.

All these numbers are theoretical. The real amount of current/power each output can deliver is limited by other components, especially by the coils used on each output.

Figure 13: +3.3 V, +5 V and +12 V rectifiers.

The outputs are monitored by a PS224 integrated circuit, which supports over voltage (OVP), under voltage (UVP) and over current (OCP) protections, supporting two +12 V channels.

Figure 14: Monitoring integrated circuit.

All capacitors from the secondary are also from Teapo.

[nextpage title=”Power Distribution”]

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

Figure 15: Power supply label.

This power supply has two +12 V rails (the monitoring integrated circuit really provides monitoring for two +12 V channels and we could clearly see the two current sensors installed on the printed circuit board), distributed like this:

• +12V1: The cables that are permanently attached to the power supply.
• +12V2: The cables from the modular cabling system.

This distribution is perfect, as it put the CPU and the video card on separated rails.

Now let’s see if this power supply can really deliver 600 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 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 +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 +12V2 rails, while the +12VB input was connected to the power supply +12V1 rail (EPS12V connector).

Input	Test 1	Test 2	Test 3	Test 4	Test 5
+12VA	4 A (48 W)	9 A (108 W)	13 A (156 W)	17.5 A (210 W)	21.5 A (258 W)
+12VB	4 A (48 W)	9 A (108 W)	13 A (156 W)	17.5 A (210 W)	21.5 A (258 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 (5 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)	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	116.3 W	244.8 W	359.3 W	484.1 W	600.4 W
% Max Load	19.4%	40.8%	59.9%	80.7%	100.1%
Room Temp.	48.4° C	47.5° C	46.8° C	45.6° C	42.5° C
PSU Temp.	45.3° C	46.0° C	46.7° C	47.6° C	42.4° C
Voltage Regulation	Pass	Pass	Pass	Pass	Pass
Ripple and Noise	Pass	Pass	Pass	Pass	Pass
AC Power	136.6 W	282.8 W	420.7 W	579.6 W	733.0 W
Efficiency	85.1%	86.6%	85.4%	83.5%	81.9%
AC Voltage	114.9 V	113.4 V	112.3 V	110.5 V	109.5 V
Power Factor	0.977	0.99	0.994	0.996	0.998
Final Result	Pass	Pass	Pass	Pass	Pass

OCZ ModXStream Pro 600 W can really deliver its labeled power, however during test five it shut down twice.

We were actually surprised with its performance. Since it has “only” the standard 80 Plus certification, we were expecting to see a unit with 80-82% efficiency across the board, but we are happy to be wrong: OCZ ModXStream Pro 600 W could achieve a high efficiency between 83.5% and 86.6% when we pulled up to 480 W. At full load (600 W) efficiency was at 81.9%, which is great – in fact these results are almost enough for this unit to get the 80 Plus Bronze certification.

Voltage regulation was outstanding, with all voltages within 3% from their nominal values – i.e., values closer to their “face value” than required, as the ATX12V specification allows voltages to be within 5% from their nominal values (10% for -12 V).

And then we have noise and ripple, which were below the maximum allowed (during test five -12 V output touched the 120 mV limit and +12 V was a little higher than we’d like to see, but still within specs). Below you can see the results during test five. The maximum allowed is 120 mV on +12 V and 50 mV on +5 V and +3.3 V. All these numbers are peak-to-peak figures.

Figure 16: +12VA input from load tester at 600.4 W (80.2 mV).

Figure 17: +12VB input from load tester at 600.4 W (80.6 mV).

Figure 18: +5 V rail with power supply delivering 600.4 W (30.2 mV).

Figure 19: +3.3 V rail with power supply delivering 600.4 W (18.8 mV).

Unfortunately we couldn’t pull any more power from this unit. If we tried to increase one amp on any output the unit would shut down.

[nextpage title=”Main Specifications”]

OCZ ModXStream Pro 600 W power supply specs include:

• ATX12V 2.2
• EPS12V 2.91
• Nominal labeled power: 600 W.
• Measured maximum power: 600.4 W at 42.5° C.
• Labeled efficiency: 86% at typical load (i.e., at 300 W), 80 Plus Standard certification
• Measured efficiency: Between 81.9% and 86.6% at 115 V (nominal, see complete results for actual voltage).
• Active PFC: Yes.
• Modular Cabling System: Yes, partial.
• Motherboard Power Connectors: One 20/24-pin connector, one ATX12V connector and one EPS12V connector (all permanently attached to the power supply).
• Video Card Power Connectors: One six-pin connector and one six/eight-pin connector in separated cables (modular cabling system).
• SATA Power Connectors: Six in two cables (modular cabling system).
• Peripheral Power Connectors: Four in two cables (modular cabling system).
• Floppy Disk Drive Power Connectors: Two in two cables.
• Protections: Over Voltage (OVP), Over Power (OPP) and Short-Circuit (SCP, tested and working). Although not listed by the manufacturer, this unit also has Under Voltage (UVP) and Over Current (OCP) protections.
• Warranty: Three years.
• Real Manufacturer: Highpower
• More Information: https://www.ocztechnology.com
• Average price in the US*: USD 80.00.

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

[nextpage title=”Conclusions”]

OCZ ModXStream Pro 600 W proved to be an outstanding mainstream 600 W power supply, surprising us at all and every level. Being an inexpensive unit that has only the standard 80 Plus certification, we were expecting it to achieve efficiency around 82-83% across the board, but in fact it could maintain efficiency between 83.5% and 86.6% when we pulled up to 480 W from it (81.9% at 600 W), almost granting it 80 Plus Bronze certification.

Voltage regulation from this unit is very tight, with all outputs within 3% from their nominal values (ATX12V specification allows a 5% tolerance – 10% for -12 V). And ripple and noise levels, although not as low as we’d like to see, were still below the maximum allowed.

This unit comes with a price tag of only USD 80 and if you live in the USA and buy it at Newegg.com you get a USD 25 mail-in rebate, making it to cost you only USD 55. Unbelievable!

The main competitor to OCZ ModXStream Pro 600 W is Cooler Master Silent Pro M 600 W, which we recently reviewed. Both achieved the same performance level, but the unit from Cooler Master has some advantages: more connectors, the cables from the modular cabling system are flat, lower noise and ripple levels, and we could pull up to 679 W from it – on this model from OCZ we couldn’t pass from the labeled 600 W. But it costs USD 100, making OCZ ModXStream Pro 600 W a bargain, being the power supply with one of the best cost/benefit ratios for the average user today.