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[nextpage title=”Introduction”]

Performance 650 W (also called RP650-2) is a new power supply from Rosewill, featuring a 120 mm fan, active PFC, two auxiliary cables for video cards and labeled as having a 730 W peak power. Is this a good product? Can it really deliver 650 W? Let’s see.

Rosewill Performance 650 WFigure 1: Rosewill Performance 650 W.

This power supply is small, being only 5 1/2” (140 mm) deep, featuring a 120 mm ball bearing fan on its bottom that glows blue when turned on and active PFC circuit. It does not feature a modular cabling system. All cables have a nylon sleeving that comes from inside the power supply housing.

Rosewill Performance 650 WFigure 2: Rosewill Performance 650 W.

The main motherboard cable uses a 20/24-pin connector and this unit comes with two ATX12V connectors that together form an EPS12V connector.

This power supply comes with six peripheral cables: One cable with one 6-pin video card auxiliary power connector, one cable with one 6/8-pin video card auxiliary power connector,  two cables with two SATA power plugs each, one cable with three standard peripheral power plugs and one cable with three standard peripheral power plugs and one floppy disk drive power plug.

We think this power supply could have more SATA power connectors (six, for example), especially because we are talking about a 650 W product.

All wires are 18 AWG, which is the correct gauge to be used nowadays.

According to Rosewill, this unit is manufactured by a company called ATNG and apparently Rosewill Performance 650 W is a rebadged APL-12CM model. Curiously there is no 650 W model on ATNG’s website.

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

[nextpage title=”A Look Inside The Performance 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.

The first thing that caught our eye when disassembling this unit was that almost all semiconductors had their markings scratched by the manufacturer, making it impossible to identify the components used. We will talk more about this later.

Rosewill Performance 650 WFigure 3: Overall look.

Rosewill Performance 650 WFigure 4: Overall look.

Rosewill Performance 650 WFigure 5: 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, providing two Y capacitors and two X capacitors more than the minimum recommended.

Rosewill Performance 650 WFigure 6: Transient filtering stage (part 1).

Rosewill Performance 650 WFigure 7: Transient filtering stage (part 2).

Now let’s have a more detailed look inside Rosewill Performance 650 W.

[nextpage title=”Primary Analysis”]

As mentioned, the problem was that the manufacturer did the favor of scratching off the markings from all semiconductors used in this power supply, preventing us from making a more in-depth analysis about the used components. We wonder why a manufacturer would do that. To prevent other companies from copying the project? As if anyone would copy a project from a manufacturer that is not even on the radar screen.

On the primary we could identify only the rectifying bridge and the PFC/PWM combo controller.

This power supply uses one KBU8K rectifying bridge in its primary, which supports up to 8 A at 100° C. This component is correctly dimensioned: at 115 V this unit would be able to pull up to 920 W from the power grid; assuming 80% efficiency, the bridge would allow this unit to deliver up to 736 W without burning this component. Of course we are only talking about this component and the real limit will depend on all other components from the power supply.

Rosewill Performance 650 WFigure 8: Rectifying bridge.

This unit has four power transistors on the primary, two for the active PFC circuit and two for the switching circuit, which uses the traditional two-transistor forward configuration. As mentioned we couldn’t identify them as they had their markings scratched.

Rosewill Performance 650 WFigure 9: Primary transistors with their markings scratched off.

The electrolytic capacitor used on the active PFC circuit is from Teapo, a Taiwanese company, and labeled at 85° C.

Even though the PWM/PFC controller integrated circuit had also its markings scratched, we could read them: this power supply uses the omnipresent CM6800 controller.

Rosewill Performance 650 WFigure 10: PWM/PFC controller.

Now let’s take a look at the secondary from Rosewill Performance 650 W.

[nextpage title=”Secondary Analysis”]

Rosewill Performance 650 W uses four Schottky rectifiers on its secondary, and only one of them – the one used on the +3.3 V output – didn’t have its markings scratched off. So we couldn’t identify the rectifiers being used on the +12 V (two) and on the +5 V (one) outputs.

The +3.3 V output is produced by one STPS2045CT Schottky rectifier, which is capable of delivering up to 20 A (10 A per internal diode at 155° C). 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%. So the maximum theoretical current the +3.3 V output can deliver is of 14 A [10 A / (1 – 0.30)] or 47 W (nowhere close to what is printed on the label, by the way). Of course the maximum current (and thus power) this line can really deliver will depend on other components, especially the coil.

Rosewill Performance 650 WFigure 11: +12 V rectifier, +5 V rectifier and +3.3 V rectifier (the other +12 V rectifier is on the opposite side).

Instead of using a monitoring integrated circuit, this power supply implement protections using discrete components. Unfortunately the integrated circuits used on this section had their markings scratched off as well.

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

[nextpage title=”Power Distribution”]

In Figure 12, you can see the power supply label containing all the power specs.

Rosewill Performance 650 WFigure 12: Power supply label.

This power supply features four +12 V virtual rails distributed like this:

  • +12V1 (yellow with black stripe wire): Auxiliary video card cable with the 6-pin connector.
  • +12V2 (solid yellow wire): Auxiliary video card cable with the 6/8-pin connector.
  • +12V3 (yellow with green stripe wire): ATX12V/EPS12V cable.
  • +12V4 (yellow with blue stripe wire): Main motherboard cable, SATA and peripheral connectors.

We think this distribution is perfect.

Now let’s 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 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.

+12V1 and +12V2 are the two independent +12V inputs from our load tester and during out tests the +12V1 input was connected to the power supply +12V1 (video card auxiliary power connector) and +12V4 (main motherboard cable and peripheral power connectors) rails, while the +12V2 input was connected to the power supply +12V3 rail (EPS12V connector).

Input Test 1 Test 2 Test 3 Test 4 Test 5
+12V1 5 A (60 W) 10 A (120 W) 14 A (168 W) 19 A (228 W) 26.5 A (318 W)
+12V2 4.5 A (54 W) 10 A (120 W) 14 A (168 W) 19 A (228 W) 22 A (264 W)
+5V 1 A (5 W) 2 A (10 W) 4 A (20 W) 5 A (25 W) 6 A (30 W)
+3.3 V 1 A (3.3 W) 2 A (6.6 W) 4 A (13.2 W) 5 A (16.5 W) 6 A (19.8 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 134.4 W 269.7 W 385.8 W 515.0 W 648.8 W
% Max Load 20.7% 41.5% 59.4% 79.2% 99.8%
Room Temp. 47.3° C 47.1° C 47.3° C 50.1° C 47.8° C
PSU Temp. 50.6° C 50.2° C 50.2° C 51.9° C 53.4° C
Voltage Stability Pass Pass Pass Pass Pass
Ripple and Noise Pass Pass Pass Pass Fail on +5VSB
AC Power 153 W 305 W 441 W 601 W 789 W
Efficiency 87.8% 88.4% 87.5% 85.7% 82.2%
Final Result Pass Pass Pass Pass Fail

The highlight from this power supply was clearly its efficiency, which was amazingly high, especially because the manufacturer says this power supply has a minimum efficiency of 79%. When we pulled up to 60% of the labeled power (up to 390%) efficiency was between 87.5% and 88.4%. When we pulled 80% of the labeled power (520 W) efficiency was still high, at 85.7%. Only at 100% load (650 W) efficiency dropped, but still above the 80% mark.

There were some problems with this power supply though. When working at 80% load noise level at +5VSB was too high (48 mV), too close to the 50 mV limit. At 100% load noise level at +5VSB was at 58 mV, above the maximum allowed. At full load noise level at +12V2 input from our load tester (which was connected to the unit’s +12V3 rail) was too high (98.6 mV), but still under the maximum allowed (120 mV). Ditto for -12 V (95 mV). All values are peak-to-peak.

And when pulling 650 W from this unit, it shut down after two minutes, when some protection kicked in (most probably the overload or over temperature protection). This seems to be a textbook example of a power supply labeled at 25° C, a temperature that is never reached inside the PC case (power supplies lose their ability to deliver current and thus power with temperature). We test power supplies at more realistic temperatures, between 45° C and 50° C.

Rosewill Pwerformance 650 WFigure 13: Noise level at +12V1 with the reviewed power supply delivering 648.8 W (76.4 mV).

Rosewill Pwerformance 650 WFigure 14: Noise level at +12V2 with the reviewed power supply delivering 648.8 W (98.6 mV).

Rosewill Pwerformance 650 WFigure 15: Noise level at +5 V with the reviewed power supply delivering 648.8 W (32.2 mV).

Rosewill Pwerformance 650 WFigure 16: Noise level at +3.3 V with the reviewed power supply delivering 648.8 W (39.8 mV).

Now let’s see if we can pull even more power from Performance 650 W.

[nextpage title=”Overload Tests”]

Before overloading power supplies we always test first if the over current protection (OCP) circuit is active and at what level it is configured. For this test we installed only cables that were connected to the unit’s +12V4 rail (main motherboard cable and peripheral plugs) and increased current to 33 A. The unit didn’t shut down. We repeated the test but now pulling 33 A (the limit from our tester) from +12V3 (EPS12V connector) and again the unit didn’t shut down. This means that either the OCP circuit is disabled or is configured at a value above 33 A.

We could easily overload this unit to the values below. Above that the unit wouldn’t turn on, which is great. The problem was that when overloading the unit it could work only one minute or less before shutting down, just like it happened when we pulled 650 W from it. Anyway, since the overload protection was active, you won’t burn your power supply if you overload it.

Below you can see the maximum amount of current/power we could pull from this unit (but, as explained, the unit would only work one minute or less under this configuration). Noise level was outside specs, at 190 mV on +12V2 input.

Input Maximum
+12V1 31 A (372 W)
+12V2 31 A (372 W)
+5V 6 A (30 W)
+3.3 V 6 A (19.8 W)
+5VSB 2.5 A (12.5 W)
-12 V 0.5 A (6 W)
Total 806 W
% Max Load 124%
Room Temp. 47.8° C
PSU Temp. 53.4° C
AC Power 1,012 W
Efficiency 79.6%

[nextpage title=”Main Specifications”]

Rosewill Performance 650 W (RP650-2) power supply specs include:

  • Nominal labeled power: 650 W continuous, 730 W peak.
  • Measured maximum power: 515 W at 50° C continuous, 806 W at 47.8° C peak.
  • Labeled efficiency: Above 79%.
  • Measured efficiency: Between 82.2% and 88.4% at 115 V.
  • Active PFC: Yes.
  • Modular Cabling System: No.
  • Motherboard Power Connectors: One 20/24-pin connector and two ATX12V connectors that together form one EPS12V connector.
  • Video Card Power Connectors: One 6-pin connector and one 6/8-pin connector.
  • Peripheral Power Connectors: Six in two cables.
  • Floppy Disk Drive Power Connectors: One.
  • SATA Power Connectors: Four in two cables.
  • Protections: over current (OCP, tested and not working), over voltage (OVP, not tested), under voltage (UVP, not tested), over load (OPP/OLP, apparently working), over temperature (OTP, apparently working) and short-circuit (SCP, tested and working).
  • Warranty: One year.
  • Real model: ATNG APL-12CM
  • More Information: https://www.rosewill.com
  • Suggested price in the US: USD 129.00

[nextpage title=”Conclusions”]

Although we were impressed by its efficiency, we can’t recommend Rosewill Performance 650 W.

First, it couldn’t continually deliver 650 W at a room temperature between 45° C and 50° C, being a textbook example of a unit labeled at 25° C, a temperature that is impossible to be achieved inside a computer. On the good side the power supply has its protections active, so it simply shut down when it couldn’t deliver power any longer, contrary to cheap units that explode when this happens. We know that users buying this product won’t pull 650 W from it, but if I am buying a 650 W unit I want a unit that is capable of delivering its labeled power under real-world conditions.

Also noise level at +5VSB when we pulled 650 W from this unit was above the maximum allowed.

Then we have the number of SATA power connectors, too few in our opinion. We think this unit should come with five or six SATA power connectors and not only four.

And we have the price. It has a suggested retail price of USD 129, but this is just a loose reference, because we always can find Rosewill products being sold at Newegg.com at a price far lower than the manufacturer suggested retail price – sometimes half the price.

Even if Rosewill relabeled this unit as a 550 W product and lowered its price, we would still recommend OCZ StealthXstream 600 W instead. This model from OCZ costs only USD 80 (USD 60 after a mail-in rebate) and doesn’t have the flaws we listed, and is our recommendation for the user that wants a good inexpensive power supply for a mainstream PC.