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[nextpage title=”Introduction”]
The Fractal Design Tesla R2 is available in 500 W, 650 W, 800 W, and 1,000 W versions, all with the 80 Plus Gold certification. Let’s take a look at the 650 W model, which comes with a very nice price tag.
The 650 W model (and only this model) has two color options: black or white. We reviewed the black model.
This power supply is manufactured by ATNG, using the same platform used by the Rosewill FORTRESS-650. (They are not identical; we will point out the differences between the two throughout the review.)
Figure 1: Fractal Design Tesla R2 650 W power supply
Figure 2: Fractal Design Tesla R2 650 W power supply
The Fractal Design Tesla R2 650 W is 6.3” (160 mm) deep, using a 135 mm fan on its bottom. There is no technical information available. It is a ball-bearing model, according to Fractal Design.
Figure 3: Fan
This unit doesn’t have a modular cabling system. All cables use 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, 21.6” (55 cm) long
- One cable with two ATX12V connectors that together form an EPS12V connector, 26.4” (67 cm) long
- One cable with two six/eight-pin connectors for video cards, 21.3” (54 cm) to the first connector, 3.9” (10 cm) between connectors
- One cable with three SATA power connectors, 21.3” (54 cm) to the first connector, 5.1” (13 cm) between connectors
- One cable with three SATA power connectors, 16.5” (42 cm) to the first connector, 5.1” (13 cm) between connectors
- One cable with two standard peripheral power connectors and one floppy disk drive power connector, 22.8” (58 cm) to the first connector, 4.7” (12 cm) between connectors
All wires are 18 AWG, which is the correct gauge to be used.
The cable configuration is compatible with a mainstream 650 W unit; however, some competing products have four video card power connectors instead of only two, including the Rosewill FORTRESS-650.
Figure 4: Cables
Let’s now take an in-depth look inside this power supply.[nextpage title=”A Look Inside the Fractal Design Tesla R2 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.
On this page we will have an overall look, while in the following pages we will discuss in detail the quality and ratings of the components used.
Figure 5: Top view
Figure 6: Front quarter view
Figure 7: Rear quarter view
Figure 8: The printed circuit board
[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.
In this power supply, this stage is flawless.
Figure 9: Transient filtering stage (part 1)
Figure 10: Transient filtering stage (part 2)
On the next page, we will have a more detailed discussion about the components used in the Fractal Design Tesla R2 650 W.[nextpage title=”Primary Analysis”]
On this page, we will take an in-depth look at the primary stage of the Fractal Design Tesla R2 650 W. For a better understanding, please read our “Anatomy of Switching Power Supplies” tutorial.
This power supply uses one US15KB80R rectifying bridge, attached to the same heatsink as the active PFC transistors. This component supports up to 15 A at 101° C, 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.
Figure 11: Rectifying bridge
The active PFC circuit uses one IPW50R140CP MOSFET, which supports up to 23 A at 25° C or 15 A at 100° C in continuous mode (note the difference temperature makes), or 56 A in pulse mode at 25° C. This transistor presents a 140 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 Rosewill FORTRESS-650 uses a transistor, an IPW60R99C6, with higher current limit and lower RDS(on).
The active PFC circuit is controlled by a CM6502 integrated circuit.
Figure 12: Active PFC controller
The output of the active PFC circuit is filtered by one 390 µF x 400 V electrolytic capacitor, from Teapo, labeled at 105° C. The Rosewill FORTRESS-650 uses a Japanse capacitor here.
Figure 13: Capacitor
In the switching section, two IPW60R190C6 MOSFETs are used in a resonant configuration. Each transistor supports up to 20.2 A at 25° C or 12.8 A at 100° C in continuous mode, or 59 A in pulse mode at 25° C, with a maximum RDS(on) of 190 mΩ. The Rosewill FORTRESS-650 uses two IPW50R140CP transistors here. (The specifications for these transistors were already discussed above.)
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.
Figure 15: Resonant controller
Let’s now take a look at the secondary of this power supply.[nextpage title=”Secondary Analysis”]
As one would expect in a high-efficiency power supply, the Fractal Design Tesla R2 650 W uses a synchronous design, where the Schottky rectifiers are replaced with MOSFETs. Also, the reviewed product uses a DC-DC design in its secondary. This means that the power supply is basically a +12 V unit, with the +5 V and +3.3 V outputs produced by two smaller power supplies connected to the main +12 V rail. Both designs are used to increase efficiency.
The +12 V output uses four IPP041N04N MOSFETs, each one supporting up to 80 A at 100° C in continuous mode, or up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 4.1 mΩ. The Rosewill FORTRESS-650 uses four IPP023N04N G, which provide higher current limits and a lower RDS(on).
Figure 16: The +12 V transistors
As explained, the +5 V and +3.3 V outputs are produced by two DC-DC converters, located on a daughterboard soldered to the main printed circuit board. Each converter is controlled by a CAT7523 integrated circuit and uses a pair of IPD031N03L MOSFETs, each supporting up to 90 A at 100° C in continuous mode and up to 400 A at 25° C in pulse mode, with a maximum RDS(on) of 3.1 mΩ.
Figure 17: The DC-DC converters
Figure 18: The DC-DC converters
The outputs of the power supply are monitored by a GR8313 integrated circuit, which only supports over voltage (OVP) and under voltage (UVP) protections.
Figure 19: Monitoring circuit
This power supply uses a mix of solid and electrolytic capacitors in its secondary. The electrolytic capacitors are from Teapo and labeled at 105° C, as usual. The solid capacitors are from CapXon. The Rosewill FORTRESS-650 uses Japanese capacitors here.
Figure 20: Capacitors
[nextpage title=”The +5VSB Power Supply”]
The +5VSB (a.k.a. standby) power supply is independent of the main power supply, since it is on continuously.
The +5VSB power supply uses an integrated circuit that incorporates the PWM controller and the switching transistor into a single chip. However, the manufacturer scratched off the marking on the chip, so we can’t say which model it is.
Figure 21: The +5VSB integrated circuit with an integrat
ed switching transistor
The rectification of the +5VSB output is performed by an S10C40C Schottky rectifier. This component supports up to 10 A (5 A per internal diode at 125° C, 0.55 V maximum voltage drop).
Figure 22: The +5VSB rectifier
[nextpage title=”Power Distribution”]
In Figure 23, you can see the power supply label containing all the power specs.
Figure 23: Power supply label
As you can see, this unit has a single +12 V rail configuration.
Let’s find out how much power this unit can deliver.
[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 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 and +12VB inputs were connected to the power supply’s single +12 V rail. (The +12VB input was connected to the power supply EPS12V connector.)
| 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 | 140.4 W | 272.9 W | 394.2 W | 527.4 W | 652.4 W |
| % Max Load | 21.6% | 42.0% | 60.6% | 81.1% | 100.4% |
| Room Temp. | 47.3° C | 46.4° C | 47.1° C | 49.3° C | 48.9° C |
| PSU Temp. | 47.9° C | 47.7° C | 48.0° C | 49.3° C | 49.2° C |
| Voltage Regulation | Pass | Pass | Pass | Pass | Pass |
| Ripple and Noise | Pass | Pass | Pass | Pass | Pass |
| AC Power | 154.8 W | 298.2 W | 435.8 W | 593.3 W | 755.0 W |
| Efficiency | 90.7% | 91.5% | 90.5% | 88.9% | 86.4% |
| AC Voltage | 116.8 V | 115.4 V | 114.2 V | 112.8 V | 110.6 V |
| Power Factor | 0.972 | 0.978 | 0.986 | 0.992 | 0.994 |
| Final Result | Pass | Pass | Pass | Pass | Pass |
The 80 Plus Gold certification promises efficiency of at least 87% under light (i.e., 20%) load, 90% under typical (i.e., 50%) load, and 87% under full (i.e., 100%) load. The Fractal Design Tesla R2 650 W was able to match these numbers for light and typical loads at high temperatures. At full load we saw 86.4% efficiency, a tad below the minimum promised. However, the AC voltage dropped to below 115 V, which might explain this number. Also, as we always point out, the 80 Plus tests are conducted at 23° C, and we test power supplies at higher temperatures.
Let’s discuss voltage regulation on the next page. [nextpage title=”Voltage Regulation Tests”]
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. We consider a power supply as “flawless” if it shows voltages within 3% of their nominal values. In the table below, you can see the power supply voltages during our tests and, in the following table, the deviation, in percentage, of their nominal values.
The Fractal Design Tesla R2 650 W presented excellent voltage regulation for its positive outputs, with them always within 2% of their nominal values.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | +12.14 V | +12.14 V | +12.12 V | +12.12 V | +12.10 V |
| +12VB | +12.15 V | +12.13 V | +12.12 V | +12.10 V | +12.08 V |
| +5 V | +5.05 V | +5.04 V | +5.02 V | +5.00 V | +4.98 V |
| +3.3 V | +3.34 V | +3.31 V | +3.29 V | +3.26 V | +3.24 V |
| +5VSB | +5.03 V | +5.00 V | +4.97 V | +4.94 V | +4.91 V |
| -12 V | -11.23 V | -11.40 V | -11.58 V | -11.77 V | -11.96 V |
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 1.17% | 1.17% | 1.00% | 1.00% | 0.83% |
| +12VB | 1.25% | 1.08% | 1.00% | 0.83% | 0.67% |
| +5 V | 1.00% | 0.80% | 0.40% | 0.00% | -0.40% |
| +3.3 V | 1.21% | 0.30% | -0.30% | -1.21% | -1.82% |
| +5VSB | 0.60% | 0.00% | -0.60% | -1.20% | -1.80% |
| -12 V | 6.42% | 5.00% | 3.50% | 1.92% | 0.33% |
Let’s discuss the ripple and noise levels on the next page.
[nextpage title=”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 is 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 m
aximum allowed ripple and noise levels.
The Fractal Design Tesla R2 650 W provided ripple and noise levels within specifications, as you can see in the table below. When we pulled 650 W from this unit, ripple and noise levels were too close to the maximum allowed at +5 V, +3.3 V, and +5VSB outputs.
| Input | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 |
| +12VA | 18.4 mV | 27.4 mV | 36.4 mV | 37.2 mV | 47.4 mV |
| +12VB | 18.6 mV | 28.2 mV | 37.0 mV | 36.8 mV | 46.0 mV |
| +5 V | 15.6 mV | 17.0 mV | 19.6 mV | 27.4 mV | 41.6 mV |
| +3.3 V | 16.4 mV | 17.2 mV | 20.2 mV | 26.2 mV | 42.8 mV |
| +5VSB | 15.4 mV | 18.0 mV | 22.4 mV | 30.0 mV | 47.8 mV |
| -12 V | 21.8 mV | 41.4 mV | 52.8 mV | 45.6 mV | 49.4 mV |
Below you can see the waveforms of the outputs during test five.
Figure 24: +12VA input from load tester during test five at 652.4 W (47.4 mV)
Figure 25: +12VB input from load tester during test five at 652.4 W (46.0 mV)
Figure 26: +5V rail during test five at 652.4 W (41.6 mV)
Figure 27: +3.3 V rail during test five at 652.4 W (42.8 mV)
Let’s see if we can pull more than 650 W from this unit.
[nextpage title=”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. The maximum we could pull from this power supply is listed below. During this test, ripple and noise levels at +5 V, +3.3 V, and +5VSB were above the maximum allowed. Voltage regulation was still excellent, with all voltages within 2% of their nominal values.
| Input | Overload Test |
| +12VA | 29 A (348 W) |
| +12VB | 29 A (348 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 | 818.8 W |
| % Max Load | 126.0% |
| Room Temp. | 46.6° C |
| PSU Temp. | 48.7° C |
| AC Power | 994 W |
| Efficiency | 82.4% |
| AC Voltage | 108.4 V |
| Power Factor | 0.994 |
[nextpage title=”Main Specifications”]
The main specifications for the Fractal Design Tesla R2 650 W power supply include:
- Standards: ATX12V 2.31
- Nominal labeled power: 650 W at 40° C
- Measured maximum power: 818.8 W at 46.6° C
- Labeled efficiency: 80 Plus Gold certification (87% at light/20% load, 90% at typical/50% load, and 87% at full/100% load)
- Measured efficiency: Between 86.4% and 91.5%, 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: Two six/eight-pin connectors on one cable
- SATA Power Connectors: Six on two cables
- Peripheral Power Connectors: Two on one cable
- Floppy Disk Drive Power Connectors: One
- Protections (as listed by the manufacturer): NA
- Are the above protections really available? The power supply has over voltage (OVP), under voltage (UVP), and short-circuit (SCP) protections.
- Warranty: Three years
- More Information: https://www.fractal-design.com
- Average Price in the U.S.*: USD 120.00
* Researched at Newegg.com on the day we published this review.
[nextpage title=”Conclusions”]
The Fractal Design Tesla R2 650 W proved to be a very good mainstream power supply with the 80 Plus certification, with an excellent price tag and, therefore, a recommended unit.
It is based on the same platform as the Rosewill FORTRESS-650. Rosewill’s version, however, uses slightly different components inside. Of note for the average user is the use of better capacitors, manufactured in Japan by Chemi-Con, and a total of four video card power connectors instead of only two. The model from Rosewill is also USD 10 cheaper.