Original Link: https://www.anandtech.com/show/11552/the-enermax-revolution-sfx-650w-psu-review
The Enermax Revolution SFX 650W PSU Review: Compact & Capable
by E. Fylladitakis on June 30, 2017 12:00 PM EST- Posted in
- PSUs
- Cases/Cooling/PSUs
- Enermax
- SFX
PC gaming parts are constantly getting more powerful, efficient, and affordable, which is making the PC platform a very serious rival of consoles when it comes to living room gaming. Especially since the release of the Pascal GPUs some months ago, which virtually enabled seamless 4K gaming with a single card, the number of users investing in a living room gaming PC has been increasing significantly.
When it comes to living room gaming PCs however, size is a very important factor and may even outweigh that of the cost. A large PC tower is rarely a feasible option, with users demanding small and elegant designs that match the aesthetics of a modern living room. With many reputable manufacturers offering products specifically designed for living room gaming PCs, the selection of a proper case and peripherals is not an issue. The selection of internal components however can become an ordeal, as compact cases often have numerous limitations.
In order to conserve space, either in order to make the design even smaller or to make room for other components, many compact case designs are nowadays making use of SFX power supply units. It would be impossible a few years back to power a powerful gaming system with an SFX PSU, but more recent designs are making use of more efficient energy conversion platforms and components, allowing them to reach power outputs that were unheard of for SFX PSUs a few years ago.
This year several manufacturers have released high output SFX designs, and Enermax is one of the most prominent names. The company announced the Revolution SFX units back in December, highlighting their cost-effective design and full SFX compatibility. The Revolution SFX units are available in just two variations, the ERV550SWT and the ERV650SWT, with a maximum power output of 550W and 650W respectively. In this review we are having a close look at the more powerful 650W version.
Power specifications ( Rated @ Unknown °C ) | |||||
AC INPUT | 100 - 240 VAC, 50 - 60 Hz | ||||
RAIL | +3.3V | +5V | +12V | +5Vsb | -12V |
MAX OUTPUT | 18A | 15A | 54A | 3A | 0.3A |
90W | 648W | 15W | 3.6W | ||
TOTAL | 650W |
Packaging and Bundle
Enermax went with a minimalistic, dark design for the packaging of their SFX PSUs, with icons highlighting its most important features. The thick walls of the cardboard box and the polystyrene foam pieces inside offer more than ample shipping protection to the small unit.
Inside the box we found a luxurious bundle that we rarely encounter even with top tier products. Enermax supplies a typical manual, four black mounting screws, a SFX to ATX adapter for the installation of the PSU in an ATX-compliant case, two long and two short cable management straps (one of each is red and the other is black), and finally a “limited edition” Bluetooth speaker (the color is random). The small speaker is not very powerful or clear, but it is an interesting (if unusual) small gift to have.
Enermax went with a fully modular design and every cable can be detached, including the 24-pin ATX cable. All of the cables are ribbon-like, “flat” type, which is the reasonable choice considering that the PSU may be installed in very confined spaces where every millimeter counts. Be warned that these cables are much shorter than those of a regular ATX unit, with the ATX cable being just 30 cm (11.8") long and the PCI-E/EPS cables only 40 cm (15.75") long. Every cable is made of black wires and black connectors.
Enermax Revolution SFX 650W (ERV650SWT) | ||
Connector type | Hardwired | Modular |
ATX 24 Pin | - | 1 |
EPS 4+4 Pin | - | 1 |
EPS 8 Pin | - | - |
PCI-E 6+2 Pin | - | 2 |
PCI-E 8 Pin | - | - |
SATA | - | 6 |
Molex | - | 4 |
Floppy | - | - |
External Appearance
Where other manufacturers expanded their designs beyond the SFX specification limits in order to fit the required components, Enermax followed the SFX specifications down to the letter. The chassis is measuring 125 × 63.5 × 100 mm / 4.92 × 2.5 × 3.94 in (W×H×D), which is the exact SFX form factor design size, ensuring that the Revolution SFX will fit inside every SFX-compliant case.
The chassis of the Revolution SFX is sprayed black, with the series logo appearing in white on every side of the PSU, even on the right side of the unit where the sticker with its electrical specifications and certifications is. Enermax’s designers clearly expected that the PSU will be installed with its fan facing upwards, otherwise the sticker will not be visible and the logos on the left side of the unit will be upside down. However, installing the Revolution SFX with the fan facing downwards will not have any repercussions other than aesthetic.
There is nothing on the rear side of the Revolution SFX other than the AC cable receptacle. In designs where every millimeter counts, even a simple on/off switch can be a luxury. The connectors for the modular cables can the seen at the front side of the unit, with a basic legend printed on the metallic chassis. The connectors should be fool proof but the 6-pin SATA/Peripheral cables can be forced into the 8-pin PCI-E/EPS connectors, in which case the inevitable result would be irreversible component damage. However, a lot of force is required, as the plastic lock of the cables will prevent their insertion in the 8-pin connectors.
Internal Design
A Yate Loon Electronics low profile 80 mm fan is responsible for the cooling of the Revolution SFX PSU. The thin fan has a sleeve bearing and a maximum rotational speed of 3000 RPM. It is strange why the company did not opt for a ball bearing engine fan instead on a unit with a 5-year long warranty. It is quite possible that the designer assumed that the fan will not be operational for more than a few hours every day, as the Revolution SFX has a semi-passive cooling design and the fan will start only after surpassing a certain load level.
A look at the interior of the Revolution SFX reveals a packed design, with barely enough space for the airflow to travel through the components. The OEM behind the Revolution SFX is Channel Well Technologies (CWT), a well-known designer and manufacturer of advanced PSU platforms.
The filtering stage is on a secondary PCB that is soldered on the AC receptacle. We measured four Y capacitors, two X capacitors and two filtering inductors in total, which are pretty much the standard configuration for an advanced 600-700W PSU.
Moving on to the APFC components, we can see a basic configuration with one transistor and one diode as the active components. The large 400V/390μF APFC capacitor is supplied by Nichicon. The primary inversion stage is relatively simple as well, with two high efficiency MOSFETs forming a typical half-bridge design.
Four MOSFETs form the synchronous rectification stage on the secondary of the main transformer, generating the 12V line of the unit. The 5V and 3.3V lines are being derived via DC to DC conversion circuits. All of the secondary capacitors, electrolytic and polymers alike, are provided by Nippon Chemi-Con, with a few stray Su’scon polymer capacitor used for filtering onto the connectors PCB. Su’scon is not a Japanese brand but Enermax advertises “100% electrolytic capacitors”, so their advertising campaign technically is accurate.
Cold Test Results
For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts. For a thorough explanation of our testing methodology and more details on our equipment, please refer to our How We Test PSUs - 2014 Pipeline post.
The efficiency of the Enermax Revolution SFX 650W PSU is very good, with the PSU meeting and surpassing the 80Plus Gold guideline with an input voltage of 230V AC. We recorded a maximum efficiency of 92.3% at 50% load, with an average efficiency across the entire nominal load range (20% to 100% of the unit's capacity) of 91.2%. What could have been a lot better is the low load efficiency of the PSU, as the performance figures take a sharp dive when the load is lower than 100 Watts, dropping down to 80.4% with a load of 65 Watts and to below 72% with a load of 30 Watts.
Enermax designed the thermal control of the Revolution SFX units to undertake a semi-fanless mode, meaning that the fan will start only after the load is greater than 195 Watts or when it is absolutely necessary. Due to its very small proportions and chockfull interior, the internal temperatures of the Revolution SFX will rise sharply before the fan starts, but they remain well below hazardous figures. Once the fan does start, the temperatures drop to relatively low levels considering the size and compactness of the design.
The small, thin fan of the Revolution SFX will be audible as soon as it starts. Its speed increases almost linearly in relation to the load, reaching noise levels that we consider uncomfortable for everyday use when it becomes heavily loaded. Assuming that it will be powering a powerful dual-GPU gaming system, the game’s sound effects are likely to mask the noise coming from the PSU, assuming that the user does not want to be discreet.
Hot Test Results
Even though they complied with the design power quality guidelines, earlier SFX PSU designs displayed poor power quality figures. More recent models, like the powerful SilverStone SX700-LPT that we reviewed last year, were greatly improved.
The Enermax Revolution SFX also delivers good voltage regulation and reasonable power quality figures. Voltage regulation on the 3.3V/5V lines is at about 2.2%, with the 12V line doing much better and maintaining a regulation of 1.5% within the nominal load range. Filtering is good on the 12V line, with our instruments recording a maximum voltage ripple of only 30 mV under maximum load. This figure is exceptional and comparable to that of the best ATX PSUs, yet the designer seems to have neglected the 3.3V and 5V lines, the filtering of which is much worse. The 3.3V and 5V lines recorded a maximum of 30 mV and 38 mV respectively with the PSU nominally loaded. With the PSUs voltage lines cross-loaded, the 5V line almost reached the design limit of 50 mV.
Main Output | ||||||||
Load (Watts) | 131.34 W | 326.08 W | 487.26 W | 646.35 W | ||||
Load (Percent) | 20.21% | 50.17% | 74.96% | 99.44% | ||||
Amperes | Volts | Amperes | Volts | Amperes | Volts | Amperes | Volts | |
3.3 V | 1.64 | 3.37 | 4.09 | 3.36 | 6.13 | 3.33 | 8.18 | 3.3 |
5 V | 1.36 | 5.07 | 3.41 | 5.02 | 5.11 | 4.99 | 6.82 | 4.96 |
12 V | 9.82 | 12.11 | 24.54 | 12.03 | 36.81 | 11.99 | 49.08 | 11.93 |
Line | Regulation (20% to 100% load) |
Voltage Ripple (mV) | |||||
20% Load | 50% Load | 75% Load | 100% Load | CL1 12V |
CL2 3.3V + 5V |
||
3.3V | 2.1% | 16 | 20 | 22 | 30 | 20 | 38 |
5V | 2.2% | 18 | 22 | 28 | 38 | 28 | 48 |
12V | 1.5% | 20 | 24 | 26 | 30 | 34 | 26 |
The energy conversion efficiency of the Revolution SFX 650W PSU takes a major hit with the unit operating inside our hotbox, suggesting that the small PSU is heavily thermally stressed. The cooling fan once again started when the load was above 150 Watts and the internal temperatures got uncomfortably high, yet not to the point that the thermal protection of the PSU would kick in. The average efficiency reduction is 2.3%, with a drop of 2.6% at 100% load, suggesting very high thermal stress.
Once again, the small cooling fan started when the PSU’s load had almost reached 200 Watts. Initially the noise levels are relatively low, yet this time the fan’s speed increases exponentially in relation to the load, with the small fan struggling to provide enough airflow for the PSU to remain operational. Although it manages to do so, the noise coming from the fan when the load is above 400 Watts is overwhelming, with a high-pitch whine that would probably be audible even through headphones. This clearly is not a typical everyday use scenario and is unlikely that the PSU will survive such abuse for prolonged periods of time, but it will remain operational under very adverse conditions should it need to.
Conclusion
High performance SFX PSUs are slowly but surely gaining ground on the market, and it was a matter of time before Enermax would join that train as well. With the Revolution SFX 650W ERV650SWT PSU, it is clear that Enermax did not try to create the most powerful or the best performing SFX PSU possible, but instead opted for a reasonably priced & high-performance unit that would be more appealing to the bulk of the market, as well as compatible with any SFX-compliant case/system.
In terms of quality, the Revolution SFX is a very well designed and made product. Channel-Well Technologies (CWT) is a reputable OEM and, despite the packed design, the operating temperatures of the PSU are reasonably low when it operates in a room temperature environment. As advertised, the PSU does have Japanese electrolytic capacitors. Some Taiwanese solid-state capacitors are present but, generally speaking, solid-state capacitors are far more reliable than their electrolytic counterparts and much less likely to be damaged. Our only concern lies with the small sleeve bearing engine fan. The designer probably assumed that the fan will not even be operational while the system is idling, allowing it to last for many years. However, we find it unlikely to last for many years if the PSU is forced to operate heavily loaded for many hours daily. Enermax does provide a 5-year warranty though, which is enough for peace of mind.
The overall performance of the Revolution SFX is about as we expected from a compact, high output SFX design. We recorded very good electrical performance figures, with voltage regulation and power quality figures that can easily compare to that of premium ATX designs. Its thermal losses however make the Revolution SFX noisy when it is heavily loaded, especially if it has to operate in adverse environmental conditions. While its efficiency does meet the 80Plus Gold standards, the small volume of the PSU and its relatively tiny cooling fan can only barely cope with the thermal energy output when the load is high. Although it does remain operational, the Revolution SFX will be overly loud if it has to operate heavily loaded.
In an interesting twist however that is likely to negate those concerns, this PSU has only two PCI-Express connectors – meaning it's only capable of powering one modern high performance graphics card. Even an overclocked gaming system with a single graphics card is highly unlikely to surpass 70% of this unit’s capacity, and it cannot be used to power a powerful dual GPU system. So Enermax is virtually playing it safe by essentially forcing the users to stay within the unit’s high efficiency range. Commercial switching PSUs rarely are designed to operate at maximum capacity for prolonged periods of time, but Enermax removed that possibility almost completely by limiting the number of connectors the unit comes with.
Ultimately we believe that Enermax delivered an overall well-balanced SFX PSU for enthusiasts that want to design compact gaming systems without breaking the bank. With its competitive electrical performance, modular design and reasonable retail price, the Revolution SFX is an excellent choice for the average modern living room gaming PC. The only dissonance about this PSU is its 650 Watts output, which the PSU is fully capable of reaching in lab conditions, but it is extremely unlikely to ever come close to with the number of connectors it offers. This is not necessarily a bad thing however because the Revolution SFX is unappealing for use with very high loads, as it would become very loud and its fan’s longevity would also become a concern. It is a product intended for the typical gamer and enthusiast that wants a high performance unit but fully intends to stay within the high efficiency (35%-65%) range of the PSU.