Original Link: https://www.anandtech.com/show/5252/enermax-platimax-750w-80-plus-platinum-arrives



Introducing the Enermax Platimax 750W

Since the introduction of the 80 Plus certifications, we've seen a slow but steady trickle down effect where labels that were once reserved for the highest of the high-end (e.g. 80 Plus Gold) have eventually reached mainstream price points. Manufacturers including FSP, Rosewill, Sparkle, and SuperFlower now sell affordable 80 Plus Gold power supplies for less than $100. But if mainstream users are now able to get 80 Plus Gold, what should the high-end market offer? Enter 80 Plus Platinum:

Those looking for maximum efficiency can now set their sights on 80 Plus Platinum PSUs, which will be new halo market for high-end—and high cost—power supplies. To reach the necessary efficiency levels (90% at 20% load, 92% at 50% load, and 89% at 100% load), some improvements are necessary that can change some of the core characteristics of a power. Improved resonant topologies, new MOSFETs for synchronous rectifying, higher switching frequencies, better drivers, and low-resistance conduction paths are just some of the things we'll see with 80 Plus Platinum. We're naturally eager to see what the new models can bring to the table, and Enermax sent us their Platimax 750W model, which uses an optimized Modu87+ design. Read on to find out if Enermax is the new efficiency king, and how it performs in other metrics.

Let's take a first look at the near future of switching power supplies. The Platimax 750W might be relatively close to the Modu87+ series (and is definitely in the running for the worst product name award, or perhaps least creative name award), but there are some interesting new details that we will cover on the following pages. It is very important to improve efficiency without impairing electromagnetic compatibility, something faster switching might impair. So let's find out if Enermax's new components and design are enough to provide the desired high efficiency, low ripple and noise, and decent voltage regulation.



Package Contents, Power Rating, and Fan

The contents in the package are very generous. Besides the so-called "CordGuard" that secures the power cord, users get some Enermax cable ties, an Enermax sticker, a user manual, and the modular cables in a separate bag. Features of the product include the 80 Plus Platinum certificate, a 5 year warranty, the improved resonant converter, and other technical refinements; we'll cover those in more detail later. There is also a "HeatGuard", which is nothing more than a temperature monitor that will continue to cool the PSU after you shut off the PC/PSU (if necessary).

According to the label the PSU has four +12V outputs rated at 25A each, which together can provide almost the entire power output (744W). Both +3.3V and +5V are specified at 24A. Those outputs can provide up to 120W, which is slightly lower than the values from most power supplies in this performance class but typically more than sufficient for modern PCs. The +5VSB at 3A is also relatively strong.

Enermax relies on its own high-quality Twister fan for cooling, with the model number EA142512W-OAB. This one has seven transparent fan blades and is based on Enermax's "Twister Bearing". The fan is rated at just 0.15A current, which is rather moderate. The fan runs at low speeds ranging from 300 to 1000RPM. Well, at least that applies to the fan in Platimax models below 1000W. Thanks to some patents, the fan has a 13.9cm diameter, but it's basically a 140mm fan.



External Impressions and Cable Configuration

The rugged and very thick material is strongly reminiscent of the Revolution85+ series. The color is charcoal gray, with a platinum-like surface around the fan grille. The grille has an Enermax logo in the middle, with a Platimax logo and a picture of a crown on both sides of the power supply. Our personal preference is that more is less when it comes to logos and such, but others might appreciate the markings on the case.

The modular plugs protrude slightly at the front of the PSU. The PCIe plug sockets have a different color than the ones for the peripheral components. The cable sleeving is high-quality, but the gold and red stripes on the sleeves don't quite fit with the 80 Plus Platinum certification. While it's not likely important for many users, there will be some that dislike the Platimax aesthetic.

Cables and Connectors

Main 24-pin 55cm fixed
ATX12V/EPS12V 4+4-pin 60cm fixed
8-pin 60cm fixed
PCIe 2x 6/8-pin (50cm) modular
2x 6/8-pin (50cm) modular
Peripheral 4x SATA (ca. 45, 60, 75, 90cm) modular
4x SATA (ca. 45, 60, 75, 90cm) modular
4x Molex (ca. 45, 60, 75, 90cm) modular
4x Molex, 1x FDD (ca. 45, 60, 75, 90, 105cm) modular

The connector configuration is satisfying. Both CPU cables are very long at 60cm. Each of the two PCIe cables reach 50cm. Altogether the model has four PCIe connectors for graphics cards. The eight SATA connectors are not bad for a 750W power rating. The FDD plug, if you still need one, is at the end of one Molex cable harness. The 24-pin and CPU cables are permanently fixed. Enermax prefers a semi-modular connector system for lower wattages; it's only if you buy the 1000W+ models that you get modular mainboard cables. It's an odd distinction, really—are fully modular PSUs someone more for "enthusiasts" that other 80 Plus Platinum power supplies? Does anyone actually detach their CPU/mainboard cables? Regardless, that's how Enermax has chosen to configure this particular model.



Switching Circuits and Components

The 750W Platimax PSU uses a multi-layer PCB design similar to the Modu87+ series, as well as similar components. The biggest difference is in the transistors, which have a slightly lower turn-on resistance. Enermax still relies on the resonant converter with Zero Voltage Switching (ZVS). Its core is the resonant circuit consisting of a capacitor and a coil; these have specific loading characteristics that make the voltage waveform nearly sinusoidal. The transistors switch at the zero-crossing, which greatly reduces power dissipation. This compensates for the slightly higher losses during saturation (which is no problem with a low resistance between drain and source).

With the improvement in efficiency, manufacturers can also reduce the heatsink size(s). However, even on the secondary side Enermax still uses through-hole components for synchronous rectification instead of SMDs (Surface Mounted Devices). The efficient MOSFETs there could even be cooled by the conductor path. With THT (Through Hole Technology) Enermax is playing it safe, but it also means the fan should be able to run at lower RPMs.

Note that the inductive components get very hot in a switching power supply, which requires additional cooling. The temperature of the chokes can heat all the neighboring components. Enermax seems to know this is a potential problem, which is one reason why they're not making this a passively or semi-passively cooled PSU.

Most of the capacitors are of Japanese make, which is nice to see. Enermax uses a buck converter for -12V, an interesting development. Not long ago -12V was regulated by a linear regulator with large voltage drops. Usually the power dissipation is not a problem on this rail, since the current is low, but even so this is an improvement.



Voltage Regulation

+3.3V Regulation/Ripple and Noise
Load Voltage
5% +0.91% (14mV)
10% +0.91% (22mV)
20% +0.30% (26mV)
50% -0.61% (32mV)
80% -1.82% (14mV)
100% -3.33% (39mV)
110% -3.63% (42mV)
Crossload +12V max. +0.00%
Crossload +3.3V/+5V max. -0.30%

 

+5V Regulation/Ripple and Noise
Load Voltage
5% +1.20% (10mV)
10% +1.00% (17mV)
20% +0.80% (20mV)
50% -0.40% (20mV)
80% -1.40% (25mV)
100% -2.40% (28mV)
110% -2.60% (30mV)
Crossload +12V max. +0.60%
Crossload +3.3V/+5V max. -0.40%

 

+12V Regulation (Worst Rail)/Ripple and Noise (Worst Rail)
Load Voltage
5% +1.92% (18mV)
10% +1.92% (34mV)
20% +1.83% (38mV)
50% +1.50% (51mV)
80% +1.25% (64mV)
100% +1.08% (67mV)
110% +0.83% (67mV)
Crossload +12V max. +1.08%
Crossload +3.3V/+5V max. +0.83%

Noise Levels

Acoustic Noise Impressions
Load Opinion
5% low fan noise
10% low fan noise
20% low fan noise
50% low fan noise
80% low fan noise
100% fan noise
110% fan noise

Efficiency and PFC

115VAC. 60Hz
Load Efficiency PFC
5% 77.53% 0.799
10% 86.93% 0.872
20% 88.79% 0.927
50% 92.20% 0.965
80% 91.46% 0.975
100% 89.09% 0.979
110% 88.71% 0.981

At 10% load the power supply reaches a higher efficiency than many power supplies reach at their optimal output. With a starting value of just under 0.8 that quickly scales into the >0.92 range, the power factor is relatively high as well. More than 92% efficiency can be achieved during 50% load, which is an awesome result. Moreover the PSU doesn't mind the crossload tests with different loads on the outputs; the voltage is always within ATX specification. Nevertheless the voltage on the 3.3V output could be higher while ripple and noise should be much lower on this output since this is a high-quality product.

As far as acoustics are concerned, the fan is almost always near-silent. It's only at 100% load that the fan becomes noticeable, but considering the 750W power output you would likely have several other components generating more noise to even reach that level (e.g. CPU and GPU fans).

Overall, the performance of the Platimax 750W is very good—just as we'd expect from a halo product. What's a bit surprising, however, is that our test sample technicallly failed to achieve the required 90% efficiency at 20% load for 80 Plus Platinum certification. Of course, there are differences in test environments and that may be the reason we "only" managed 89% efficiency instead of 90% efficiency. Since we're not the people doing the actual certification, we'll leave it there.



Conclusion

The Enermax Platimax 750W is a very efficient and expensive power supply. There are no significant disadvantages with the design and technology, though you'll have to pay for the privilege. The connector configuration is very good, and both the choice of components and the power supply case are very high quality. Enthusiasts looking for great performance will find this power supply a suitable solution.

Internally, Enermax uses a modified Modu87+ design with better semiconductors. The PCB material and the electrolytic capacitors in this PSU are top quality parts. The output side of the resonant converter is complemented by full-wave synchronous rectification (with MOSFETs), minimizing switching losses and the voltage drop the Schottky diodes usually have. There are a few other smaller changes as well, such as the buck converter for -12V and the "improved" EMI filtering with fewer components. We mentioned the low power output on the +3.3V and +5V rails, but this is not necessarily a disadvantage. As always, the required power depends on the system.

A modern PC pulls the majority of the current from the +12V output(s), so it's not so much the quantity but the quality of the smaller outputs that is important. Some sensitive logic gates on the motherboard need a stable 3.3V output but only low currents. The voltage drop under high load is negligible and is simply a reflection on the sizing of the converters. A low output ripple and noise is more decisive. During the load test +3.3V drops to a minimum of -3.63% below the reference value while +5V drops by as much as -2.4% to -2.60% during overload.

Even at 10% load the Platimax 750W reaches 86.93% efficiency, a remarkable value. The power factor is also very high. Low ripple and noise on most output voltages is advantageous as well. With 0.9% ripple (1% is allowed) +3.3V is the worst output. We would like to see better results here, since this is a high-end product. Apart from that the Platimax hardly blinks when confronted with our crossload tests. The voltages are always very close to their ideal value. If you don't put too many amps on +5V and +3.3V, you might even say Enermax shows flawless results.

In any case the noise of the fan is impeccable. Enermax has promised to use a low speed regulation for the Twister fan, which is true. Apart from the audible noise under full load the PSU is always nearly silent. There's also no noise from the electronics (not that we would expect anything less from a high-end PSU).

Enermax delivers an adequate cable configuration, similar to what other manufacturers offer. Four 6/8-pin PEG and 16 peripheral connectors are fairly average in this performance class, as are the 4+4-pin and 8-pin connectors for CPU power. The colorful sleeving can be described as high-grade (even if gold and red is the "wrong" color for this PSU) , and the contents of the package are satisfying. For the larger Platimax models you can even get a case fan for free. Enermax offers everything you might want from a PSU, with a few extras just for good measure.

The Platimax series includes 600W, 750W, 850W, 1000W, and 1200W models—and several of the lower wattage models have mail-in rebates available, if you're interested. The 750W we're reviewing can currently be had for $200, with a $30 MIR bringing the cost down to just $170. The largest competition for the 750W Platimax might just be Enermax's own Modu87+ 700W, which has a lower base price of $180 but no MIR. According to our research that model is not fundamentally different and is sometimes (depending on rebates) cheaper. However, when we are talking about power supplies, even small details make the difference.

Note that the only direct 80 Plus Platinum alternative comes from SuperFlower/Kingwin. The Kingwin LZP-750 (made by SuperFlower) is just as expensive as the Enermax Platimax 750W (slightly more, actually), and it's missing some features such as OCP, a MOV, and similar protections. Beyond that the LZP-750 (or SuperFlower Golden King Platinum—which is even worse than Platimax as far as names go!) offers fewer connectors. For that reason we would recommend the Platimax 750W, but only for those who demand every ounce of efficiency. If you're more of a mainstream user and can live with 1-2% less efficiency, you can certainly save some money, but it's clear that Enermax is a leading company for high-quality products.

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