PowerColor Extreme 850 W Power Supply Review
By Gabriel Torres on November 18, 2010


Introduction

The traditional video card manufacturer PowerColor decided to enter the power supply market. Let’s see if their 850 W unit (a.k.a. PX-850W) is a good product.

We couldn’t determine the OEM they are using. The printed circuit board carry the model number, “SL-850EPS,” which may indicate that this unit is manufactured by Solytech. But this is just a guess.

PowerColor Extreme 850 W power supply
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Figure 1: PowerColor Extreme 850 W power supply

PowerColor Extreme 850 W power supply
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Figure 2: PowerColor Extreme 850 W power supply

The PowerColor Extreme 850 W is 7.1” (180 mm) deep, with a 140 mm ball bearing fan (Globe Fan RL4XB1402512HH, 135.74 cfm, 1,800 rpm, 36.7 dBA).

The new PowerColor Extreme 850 W has a modular cabling system with eight connectors. The power supply comes with the following cables:

All wires are 18 AWG, which is the minimum recommended gauge, except the wires used on the main motherboard cable, which are thicker (16 AWG).

We’d like to see at least eight SATA power connectors on a 850 W power supply. Also, we'd like to see six connectors for video cards on an 850 W power supply, which would allow us to connect up to three video cards that require two power connectors each without the use of adapters.

PowerColor Extreme 850 W power supply
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Figure 3: Cables

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

A Look Inside The PowerColor Extreme 850 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. 

PowerColor Extreme 850 W power supply
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Figure 4: Top view

PowerColor Extreme 850 W power supply
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Figure 5: Front quarter view

PowerColor Extreme 850 W power supply
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Figure 6: Rear quarter view

PowerColor Extreme 850 W power supply
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Figure 7: 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. 

The PowerColor Extreme 850 W has all the required components, plus two additional Y capacitors and one additional X capacitor.

PowerColor Extreme 850 W power supply
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Figure 8: Transient filtering stage (part 1)

PowerColor Extreme 850 W power supply
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Figure 9: Transient filtering stage (part 2)

In the next page we will have a more detailed discussion about the components used in the PowerColor Extreme 850 W.

Primary Analysis

On this page we will take an in-depth look at the primary stage of the PowerColor Extreme 850 W. For a better understanding, please read our Anatomy of Switching Power Supplies tutorial.

This power supply uses one TS25P06G rectifying bridge, which is attached to an individual heatsink. This bridge 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 limit will depend on all the other components in this power supply.

PowerColor Extreme 850 W power supply
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Figure 10: Rectifying bridge

The active PFC circuit uses two SPW32N50C3 MOSFETs, which are capable of delivering up to 32 A at 25° C or up to 20 A at 100° C (note the difference temperature makes) in continuous mode, or up to 96 A in pulse mode at 25° C, each. These transistors present a 110 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 achieve a higher efficiency.

PowerColor Extreme 850 W power supply
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Figure 11: Active PFC diode and transistors

The electrolytic capacitor used to filter the output of the active PFC circuit is from Toshin Kogyo (TK), and labeled at 105° C. Even though this is a Japanese company, they sell rebranded Taiwanese products, from OST.

In the switching section, another two SPW32N50C3 MOSFET transistors are used, installed in the traditional two-transistor forward configuration.

PowerColor Extreme 850 W power supply
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Figure 12: Switching transistors

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

PowerColor Extreme 850 W power supply
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Figure 13: Active PFC/PWM combo controller

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

Secondary Analysis

This power supply has six Schottky rectifiers attached to the secondary heatsink.

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 uses four DSSK40-006 Schottky rectifiers (40 A, 20 A per internal diode at 130° C, maximum voltage drop of 0.60 V). Of the eight available diodes (two per rectifier pack), three are used for the direct rectification and five are used in for the “freewheeling” portion of the rectification. This configuration gives us a maximum theoretical current of 86 A or 1,029 W for the +12 V output.

The +5 V output uses one DSSK60-0045B Schottky rectifier (60 A, 30 A per internal diode at 120° C, maximum voltage drop of 0.68 V), giving us a maximum theoretical current of 43 A or 214 W for this output.

The +3.3 V output uses another DSSK60-0045B Schottky rectifier, giving us a maximum theoretical current of 43 A or 141 W for this output.

PowerColor Extreme 850 W power supply
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Figure 14: +5 V, +12 V and +3.3 V rectifiers

The secondary is monitored by a PS232S integrated circuit. This chip supports over voltage protection (OVP), under voltage protection (UVP), over temperature protection (OTP), and six over current protection (OCP) channels (four +12 V, one +5 V and one +3.3 V), matching the number of +12 V rails advertised by the manufacturer (four). We could clearly see shunts (current sensors) attached to each +12 V rail.

PowerColor Extreme 850 W power supply
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Figure 15: Monitoring circuit

All electrolytic capacitors used in this power supply are from Toshin Kogyo (TK, rebranded OST caps), and labeled at 105° C.

Power Distribution

In Figure 16, you can see the power supply label containing all the power specs.

PowerColor Extreme 850 W power supply
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Figure 16: Power supply label

This power supply has four  +12 V virtual rails, and we could confirm this by the presence of individual over current protection circuits attached to each rail (see Figure 17). Click here to learn more about this subject.

PowerColor Extreme 850 W power supply
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Figure 17: “Shunts” (current sensors)

These rails are distributed like this:

This distribution is good, as it separates the CPU (ATX12V/EPS12V) from the video cards in separate rails. However, we think it would be smarter if the manufacturer put each of the video card power cables on separate rails. If you have only one video card, both connectors will be connected to the same rail. Maybe it would be wiser to have each connector on a separate rail.

Let’s now see if this power supply can really deliver 850 W.

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

Input

Test 1

Test 2

Test 3

Test 4

Test 5

+12VA

6 A (72 W)

13 A (156 W)

18.5 A (222 W)

25 A (300 W)

31 A (372 W)

+12VB

6 A (72 W)

12 A (144 W)

18.5 A (222 W)

25 A (300 W)

31 A (372 W)

+5V

2 A (10 W)

4 A (20 W)

6 A (30 W)

8 A (40 W)

10 A (50 W)

+3.3 V

2 A (6.6 W)

4 A (13.2 W)

6 A (19.8 W)

8 A (26.4 W)

10 A (33 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

175.7 W

354.8 W

519.8 W

696.4 W

854.2 W

% Max Load

20.7%

41.7%

61.2%

81.9%

100.5%

Room Temp.

46.0° C

46.2° C

47.6° C

45.0° C

47.5° C

PSU Temp.

48.1° C

48.6° C

49.5° C

50.7° C

53.3° C

Voltage Regulation

Pass

Pass

Pass

Pass

Pass

Ripple and Noise

Pass

Pass

Pass

Pass

Pass

AC Power

214.1 W

417.5 W

617.0 W

842.0 W

1072.0 W

Efficiency

82.1%

85.0%

84.2%

82.7%

79.7%

AC Voltage

113.1 V

111.0 V

109.3 V

106.2 V

102.9 V

Power Factor

0.981

0.989

0.991

0.993

0.985

Final Result

Pass

Pass

Pass

Pass

Pass

The PowerColor Extreme 850 W can really deliver its labeled wattage at high temperatures.

Efficiency was very decent when we pulled up to 80% of the unit’s labeled wattage (i.e., up to 680 W), between 82% and 85%. At full load, however, efficiency dropped below the 80% mark. This unit has the 80 Plus Bronze certification, however during the 80 Plus certification power supplies are tested at only 23° C, while we tested this particular unit at 47.5° C, and efficiency drops with temperature. We've seen this kind of problem happening over and over again.

Voltage regulation was very good, with all voltages within 3% of their nominal values, except +5 V during tests one and two (still inside the proper range, though). The ATX12V specification allows voltages to be up to 5% from their nominal values (10% for the -12 V output). Therefore this power supply presents voltages closer to their nominal values than necessary most of the time.

Noise and ripple levels, although below the maximum allowed, were high during test five, almost touching the limit. Below you can see the results for the power supply outputs during test number five. The maximum allowed is 120 mV for the +12 V and -12 V outputs, and 50 mV for the +5 V, +3.3 V, and +5VSB outputs. All values are peak-to-peak figures.

PowerColor Extreme 850 W power supply
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Figure 18: +12VA input from load tester during test five at 854.2 W (101.2 mV)

PowerColor Extreme 850 W power supply
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Figure 19: +12VB input from load tester during test five at 854.2 W (96.6 mV)

PowerColor Extreme 850 W power supply
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Figure 20: +5V rail during test five at 854.2 W (37.2 mV)

PowerColor Extreme 850 W power supply
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Figure 21: +3.3 V rail during test five at 854.2 W (37.2 mV)

Let’s see if we can pull even more from the PowerColor Extreme 850 W.

Overload Tests

Below you can see the maximum we could pull from this power supply. We couldn’t pull more than that because the power supply shut down, showing that its protections are working just fine.

Input

Overload Test

+12VA

31 A (372 W)

+12VB

31 A (372 W)

+5V

16 A (80 W)

+3.3 V

16 A (52.8 W)

+5VSB

3 A (15 W)

-12 V

0.5 A (6 W)

Total

906.4 W

% Max Load

106.6%

Room Temp.

44.4° C

PSU Temp.

53.6° C

AC Power

1,154 W

Efficiency

78.5%

AC Voltage

101.4 V

Power Factor

0.996

Main Specifications

The specs of the PowerColor Extreme 850 W include:

Conclusions

The new PowerColor Extreme 850 W isn’t a bad power supply, but it has a few flaws. It should have come with at least eight SATA connectors instead of only six, six video card connectors instead of four, it should be able to achieve better efficiency at full load under real-world temperatures, and its noise and ripple levels, although below the maximum allowed, were too high for us to consider this unit as a “flawless” product.

Its success will depend on the price it will reach the market. We think the correct price for this power supply is anything up to USD 130. If it arrives on the market costing more than that, forget it, as you can buy far better 850 W units, like the XFX 850 W Black Edition (USD 150).

Originally at http://www.hardwaresecrets.com/article/PowerColor-Extreme-850-W-Power-Supply-Review/1134


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