Enermax Platimax 750W - 80 Plus Platinum Arrives
by Martin Kaffei on February 10, 2012 6:00 PM EST- Posted in
- Cases/Cooling/PSUs
- PSUs
- 80Plus
- 750W
- Enermax
- 80Plus Platinum
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.
Facebook
Twitter
RSS
47 Comments
View All Comments
ssj3gohan - Sunday, February 12, 2012 - link
In this sentence:"(...) This compensates for the slightly higher losses during turn-on (which is no problem with a low resistance between drain and source). (...)"
you imply that the drain-source resistance has something to do with the switching losses. This is not the case! Let me explain: there are two types of losses associated with power transistors: on-state losses and switching losses. On-state losses are incurred when the transistor is fully on and conducting current; it's simply the drain-source on-state resistance (R(DS, on)) times current squared. Then there's losses associated with the transition from off to on, or from on to off. At this moment, the transistor doesn't instantaneously turn on or off, but enters its linear region. At this time, both high voltage and current exist simultaneously over and through the device, which means P=I*U=high losses. You can't fix this with lower on-state resistance because the transistor is not in its on-state, it is in some state in between. This transient period is only very short (tens of nanoseconds) but if you switch really fast, e.g. 200kHz+ which is what happens in some power supplies, the losses add up quickly. The only way to combat these losses is:
- Making either I, or U, or both zero at switching time (zero current, zero voltage switching [ZVS, ZCS])
- Making the transient period as short as possible (which in practice means reducing gate charge or if possible using better drivers)
That last bit is pretty much a no-go for modern supplies because it causes noise spikes, hence the advent of ZCS and ZVS.
Martin Kaffei - Sunday, February 12, 2012 - link
I know. This might be a translation failure.The previous sentence is already about turn-on ("switching"), so this one was about the next phase.
In this case I meant saturation (no sure if this is the correct word in English).
kenyee - Sunday, February 12, 2012 - link
I.e., is it small enough to fit in actual HTPC cases?86% efficiency at 10% load makes it enticing... :-)
Lithium466 - Monday, February 13, 2012 - link
It seems that the 5Vsb rail is not protected, and that overloading it (with more than 4A) will permanently destroy the power supply...Have you tried it ? Is is true ?
ShieTar - Monday, February 13, 2012 - link
Apparently 20% are specified to be 20% on each rail, for each voltage, (see the qualification test report here: http://www.plugloadsolutions.com/psu_reports/ENERM... ).To me, this seems to be a bit less than realistic. In normal day usage, I would expect the 12V rail to be the one that really changes between idle and load cases, with the other voltages remaining at a relatively constant, and rather low, load.
Would it be possible to test efficiency at a few realistic load cases on top of the ones used by the specification? This would be really interesting to see.
86waterpumper - Monday, February 13, 2012 - link
I agree that alot here run higher end gaming rigs and may use 750 watts of power or even more. I also say that alot here are more likely to have htpcs, servers, and secondary systems somewhere in their house they themselves have built. Then you have the times when a friend or family member wants you to build a system for them to do light tasks. It doesn't always make sense to use a pico type supply for these and there is a gap between say 200 watts and 400/450 watt psus. For all these reasons it is past due time that we get some more efficient lower watt supplies. Right now my main system is a 2500k using the onboard hd3000 video I can play games fine since I have dual older 4:3 monitors still. I currently am using a x-400 seasonic and it's great but I really wish there had been a x-200, 250 or 300 instead.There will be a need for high end video cards for those that want to run huge monitors, but as onboard graphics get better and better we will see a shift where people who don't game all the time or want to blow 500 bucks on a video card are content with using onboard. It would be like if chevrolet decided to ONLY make the camaro and corvette fuel efficient and did not care about the compact cars it just does not make sense. I think psu manufacturers are missing the boat in a way but I'm also sure they are afraid that people will not pay a premium for a psu unless it has big watt numbers...
Iketh - Monday, February 13, 2012 - link
My thoughts exactly. I'm sick of using 400w power supplies to power 50-100w. I've even thought of the possibility of tapping into the wires or finding splitters for every plug so I can run 2-3 systems off one power supply.