Cooler Master Silent Pro Hybrid 1300W Power Supply Review

Today’s power supply comes to us courtesy of Cooler Master. Rather than starting us off with a mid-range unit they went straight to the top! Hence we have the Cooler Master Silent Pro Hybrid 1300 W power supply to review today. The name is huge, the rated output is huge, the box the PSU comes in is far from small, it looks like “big” might be today’s theme.

Specifications and Features

First up, the Cooler Master specification chart, direct from coolermaster-usa.com:

Tons of connectors? Check. 1300 W? Check. Every protection you can think of? Check. Juicy warranty? Check. Nothing missing here, there is some extra stuff though, such as the “fan cable 3 pins x 3”. Fan cable? Well yes, we’ll get to that. First though, the features list from Cooler Master. My thoughts on the features will be in italics.

• Silent Pro hybrid 1300 W is part of Cooler Master’s first fully modular power supply series with integrated dual 7 V fan ports. It utilizes a single powerful +12 V rail that operates at over 90% efficiency and carries an 80Plus Gold certification. 7 V fan output ports? Why yes!
• A fan speed controller is included in the package. It occupies a 5.25” drive bay and enables a user to control the Silent Pro Hybrid 135 mm Silent Hydraulic Bearing fan along with up to three system fans.

That’s a pretty solid list, the real stand out features are the fully modular cables and the fan controller. Fully modular cables means that even the ATX24P connector disconnects from the PSU, making cable routing a snap. The fan controller can control external fans as well as the PSU fan, which is interesting. I’d be leery about giving control over the PSU fan to people, personally.

Lastly for the features and specifications, the output chart. Cooler Master’s site doesn’t have the chart on it, so I’ll use a shot of the label on the PSU itself:

Here we see a fairly standard 150 W combined 3.3 V and 5 V output, a staggering 1260 W 12 V output, a slightly lower than average 15 W 5 Vsb output, and an unheard of 1.8 A 7 V output. I’m very happy to see a 7 V rail, as this saves people from having to splice resistors into their fan wires or use the highly dubious “7 V” mod to run fans at a voltage between 5 V and 12 V.  1.8 amps of 7 V should be plenty for the average user.

The features list didn’t mention DC-DC regulation of the secondary rails, but given the output chart above as well as the 80+ Gold efficiency, I would be very surprised if this unit used anything but DC-DC regulation for the secondaries.

Last in this section are my thoughts on single rail power supplies vs multi-rail power supplies:

Single rail designs are less expensive to manufacture than multiple rail designs, but these days that’s really the only benefit.  If you’re interested in how the single rail craze started keep reading, otherwise skip to the next paragraph now as there is a rough history lesson incoming! Back in the early days of the ATX specification multiple 12V rails were mandatory, one rail for the CPU and one rail for everything else at bare minimum. All PCIe connectors had to go on the same rail as well. As GPUs started consuming more and more power and people started running two, three, or even four GPUs this became an incredibly large load, and the multi-rail PSUs that followed the ATX spec were hitting OCP (OverCurrent Protection) on the PCIe rail and shutting down. The grand idea was to say “To hell with ATX spec!” and go to a single rail design. Now the PCIe connectors could draw as much as they wanted (up to the limit of the PSU of course) and the problem was solved. The difficulty is that the problem could have been solved simply be spreading the PCIe connectors out over multiple rails and/or raising the OCP point of the rails the PCIe connectors were on, while retaining the safety of having multiple rails with individual OCP. That is exactly what modern multi-rail PSUs do, and it works well. The other reason single rail designs are still around is that every rail needs dedicated hardware to monitor the current loads for OCP and while that adds to the cost of the PSU. Anyway, to my mind having a single rail isn’t really a selling point, but it isn’t really an issue either.

Pictures

First, the box!

The scale of the box isn’t very obvious in the pictures, it’s about 8″ wide though. Not small.  Not lightweight, either. Let’s open it!

Now that we’ve found the PSU, let’s look at all the cables and accessories, as well as the PSU itself.

As you can see in the photos above this really is a fully modular PSU! This makes me happy. Also exciting are the pair of 7 V fan connectors. Nice normal three pin fan plugs with room for a four pin PWM fan connector, though the PWM feature won’t be used obviously.

Everything is looking pretty good here! The PSU looks very nice indeed, you get plenty of cables and the cables themselves are ribbon style stealth black. The ATX24P cable is a bit odd in that the 3.3 V sense wire is totally in parallel with one of the 3.3 V wires, it’s literally doing nothing. The 3.3 V sense wire is a legacy piece to begin with, but it would be nice to see it wired so it was useful, just because. Also of note is that this is a straight ATX24P connector, not a 20+4. If you have an old motherboard with a 20 pin connector you may have issues. Of course, if you have that old of a motherboard you probably don’t have the hardware to need a 1300 W PSU in the first place!

All the PCIe cables are 6+2 style and both CPU power cables are 4+4. I would have liked to see one CPU power cable with a straight up EPS12v 8p connector, but that’s just me being picky.

Next, a quick look at the fan controller that comes with this unit.

Fan Controller Pictures, Features, Specifications, Testing and Dissection

As you can see above the fan controller has two knobs and a switch, along with one (long) cable to attach it to the PSU and three (longish) fan extension cables. The switch enables or disables the ability to use one of the knobs to directly control the PSU fan. This is a fairly cool feature, though one that makes me rather nervous as there isn’t a PSU temperature display on the fan controller. It may be that the PSU will override the controller if it starts overheating due to a juicy load and low fan controller setting, that’s what I would do if I were designing this thing.

The other knob controls the three fan outputs you can see on the rear of the controller, via three LM317T voltage regulators. It looks like Cooler Master spent their budget on the PSU primarily and took the easy (and inexpensive) way out and used linear regulators rather than the significantly more complicated route of a buck converter type regulator. The plus side is that linear regulators are far cheaper, the minus side is that they have a voltage drop even when set to their highest output voltage. In the case of this fan controller “full” means 10.4-10.7 V with no load on it, and with any load to speak of “full” means 9.86 V with the regulators at room temp. As you put a larger load on it the regulators get warmer, and as they warm up their minimum voltage drop actually gets lower. I’m at a bit of a loss to explain this, but the datasheet says so and my testing backs it up. With three 0.40 amp fans plugged in the “full speed” setting has risen from 9.86 V to 10.14 V as the regulators have warmed up.

Each regulator is good for at least 1.5 A (and at most 3.4 A, exactly how much varies randomly, the average is 2.2 A) according to their datasheet, the fan controller has three of them connected in parallel for a theoretical maximum of 4.5-10.2 A, I don’t think I would go that high, personally. The manual has little to say on the matter, the page pictured above is the only one that mentions the “function panel” at all. I’d guess that if the regulators have a bit of airflow over them you could probably run three to four amps of fans or so without issues and with more airflow 4.5 shouldn’t be an issue, but that is just a guess! The PCB has nice wide traces, but not wide enough that I’d recommend trying for the theoretical maximum of 10 amps.

The datasheet also states that the regulators have over-power protection and thermal protection, so in theory they should be hard to overload and/or overheat. My feeling is that he who trusts things to survive abuse ends up with a lot of dead stuff. Be aware that they are rated to run at 125 °C, so a fingertip temperature test may burn your fingertip despite the regulators still functioning happily.

The PSU fan control knob is nice and smooth, the system fan control knob is a bit tough to turn through the middle part of its travel, and the design doesn’t give you much to hold onto. This can make it a bit difficult to adjust at times, it’d be nice if the action were easier and/or there were larger knurls for fingertip traction.

The PSU fan status (auto or manual) LEDs are a nice blue color, they’re bright enough to stand out but are definitely not blinding. If you dislike them, the leads are quite accessible for modification, though that would do bad things to your warranty of course.

All told, for a free bonus accessory this fan controller works quite well, in an ideal world it would use buck regulators rather than linear, but then I expect it would not be free.

Now back to looking at the PSU.

Testing

As usual, we’ll lead off with my generic blurb on testing PSUs.

Unlike most computer parts, power supplies require rather specialized equipment to test correctly. Sure, you can plug it into a computer system and see if it can run a 980x and a couple GTX 580s, but that doesn’t tell you how much power the PSU is putting out, nor what that output looks like. Worse, if the unit is defective or simply underbuilt/overrated the unit can fail catastrophically and take your computer along with it!

Hence, you really need a load that is strong enough to stand up to a PSU dying while attached to it! Purpose built loads and the testing units to run them cost thousands of dollars. They’re easy to use and very accurate and definitely the ideal way to test power supplies, but also entirely too expensive for me to afford. Instead I have built my own! It’s entirely mechanical and not automated in the slightest, but it can put a serious load on a PSU and will survive the PSU fails in the process. The down side is that it doesn’t have the built-in current sensing that a professional grade unit does, so PSU efficiency is difficult to nail down.

The second part to a good PSU review is an oscilloscope to look at the outputs and check for ripple (I’ll talk about what ripple is in the ripple section), for this purpose I have a BK Precision model 1472B analog scope. It has its pluses and minuses compared to more modern USB scopes. On the minus side, taking pictures of it is a difficult operation at best as you’ll see. On the plus side, it has incredible sensitivity at high frequencies, something that many USB scopes lack.

Lastly, a voltage meter is required, I have a nice cheap unit that I have compared against a highly expensive Fluke 88 and found to match to within 10 mV. That’s good enough for me!

On the procedure end of things, I first check the voltages and ripple with no load on the PSU at all. This is a quite unrealistic test and many PSUs do not appreciate it at all, but I like to test it anyway. If the zero load results are terrible I put a small load on the PSU to simulate idle conditions with a low power computer and test the ripple again. Some PSUs are specifically rated for zero load operation, though this is not one of them.

With that out of the way, I put successively higher loads on the PSU and check the voltages of the three main rails at a SATA connector, all the way up to the PSU’s maximum output.

At the maximum output comes the last test, ripple at full (or very close to it) load. This does assume that the PSU didn’t explode on the way to full load of course! I’d be quite surprised if the quality PSUs I generally review were to explode, but it happens on lower end units sometimes.

The 12 V, 5 V and 3.3 V rails need to stay within 5% of their official value to stay within spec, closer is ideal of course. That means 12 V needs to be between 11.40-12.60 V, 5 V needs to be between 4.75-5.25 V and 3.3 V needs to be between 3.135-3.465 V.

With that out of the way, let’s move on to the output chart. I upgraded my PSU tester specifically to deal with this unit’s huge output rating, and I’ll be taking it to ~99.8% of its rated maximum load!

We’ll start with zero load and work our way up to that 99.8% number, and then do a bit of cross-loading. I don’t expect this unit to have any issue at all with cross-loads as it’s a DC-DC unit.

That, my friends, is a glorious looking 12 V output chart. 1.47% regulation on the 12 V rail, 2.6% on the 5 V and 4% on the 3.3 V rails. 5 V and 3.3 V didn’t do quite as well, but they’re still quite good and well within the specified range. 1.47% on the 12 V is quite tasty, and if we ignore the “unfair” zero load numbers we’re looking at an even better 1.24% on the 12 V, with the 5 V coming in at a slightly better 2.4%, while the 3.3 V rail improves dramatically to 2.47%.

Next we’ll check out the ripple this PSU has in its output voltages. Before that comes the generic ripple explanation of course.

Voltage ripple is a measurement of how far above and below the median voltage the voltage goes. To put it more simply, ripple is how much the voltage bounces around. All power supplies have some ripple due to their design, it is impossible to get rid of all of it, and very expensive to try. The more ripple in the voltage outputs the harder time components have making use of it, this is why almost every computer part out there has capacitors on it’s voltage inputs to smooth the ripple out. In the hunt for the worst of the ripple I check everywhere from 10 milliseconds per divider down to 0.5 microseconds per divider and record the worst that I find. For all of the full load tests I have loaded the entire unit down to its full rated maximum, not just the rail I am checking. For the crossload tests, the unit is loaded to the same levels as the voltage regulation cross-load tests.

The ATX12V Power Supply Design Guide calls for power supply testers to have a C1206C104K5RAC 0.1uf and a 293D106X0025D2T 10uf capacitor for ripple filtering, these capacitors simulate the input filters on devices that plug into the PSU. My tester has been updated to include these specific capacitors, rather than the similar capacitors it had previously.

The ATX spec calls for less than 120 mV of ripping on the 12 V rail and less than 50 mV on the 5 V, 3.3 V and 5 Vsb rails.

With that out of the way, onward to the ripple results! First up are zero load and half an amp load on the 5 Vsb rail. Zero load on the left.

Not bad at all!

Next up, zero load and 99.8% load on 12 V, 5 V, and 3.3 V. Zero load on the left, full load on the right.

Ripple looks excellent across the board, the 3.3 V zero load shot is literally the lowest ripple I have ever seen out of a PSU. All the ripple is well within spec, no issues here at all.

Now it’s time for cross-load ripple, on the left are the heavy 12 V load zero 3.3 V / 5 V shots, on the right are the zero 12 V heavy 3.3 V / 5 V shots.

Like most DC-DC regulation units, the Cooler Master Silent Pro Hybrid 1300 W power supply handles it like a champ, no issues here!

Fan noise at low loads was nonexistent, as the fan really does stop turning under ~200 W of load, over 200 W the fan makes a little bit of airflow noise, but no mechanical noise and nothing offensive.

At a 99.8% load the fan speeds up and makes more airflow noise but still no mechanical noise, not surprisingly the exhaust air is fairly warm!

Much to my amusement by the time I finished shutting the PSU tester’s load off the fan had cooled the PSU down enough that it decided its job was done and it stopped spinning! Also worth noting is that the fan is designed to come on at 200 W of load OR 50 °C, so if you’re up to something strange and manage to get the unit hot without a heavy load the fan will come on even at low loads.

Dissection and Component Specifications

Disclaimer: Power supplies can have dangerous voltages inside them even after being unplugged, DO NOT OPEN POWER SUPPLIES. It’s just not a good idea, and doing so could very well kill you. Don’t try this at home. Don’t try this at work. Just don’t do it.

With that out of the way, I have to admit that this is my favorite part of reviewing power supplies. So let’s get down to business and crack the lid on this unit!

First up, the fan! It’s first because it’s in the way.

I like this fan a lot, Cooler Master uses it in quite a few of their high wattage PSUs. Unfortunately, it doesn’t seem to be available for purchase separately. It moves a lot of air and doesn’t make much noise doing it. Also, bonus points to Cooler Master for putting the manufacturer (Young Lin Tech) on the fan hub, I appreciate the honesty.

With the fan out of the way, we can take a look at the unit as a whole, as well as check out the soldering on the back side of the board.

By this point I was starting to be concerned I’d have to hand out a perfect review, I’ve been saved from that fate by a soldering defect on the main PCB, as well as a piece of non-conductive glue I found under the PCB. The solder defect looks like there wasn’t quite enough solder, and maybe the component shifted slightly as the solder was hardening. In any case the far side of it was soldered well enough and the unit did great in the tests. Unfortunate to see anyway. The bit of glue is the same stuff used to hold the aPFC inductor to the PCB (as well as to make sure it doesn’t make noise), how it got under the PCB is beyond me. Other than that one soldering issue, the soldering looks excellent.

The other thing I see is that the primary heatsink has a temperature sensor of some sort on it, and the secondary heatsink has no fewer than three sensors attached to it with heatshrink! Three is a record as far as I know.

The brains of this operation reside on a fairly long daughter board, spanning most of one side of the main PCB.

From this point, we’ll go on a tour through the unit via roughly the path the power takes (let’s ignore the glaring electrical engineering issues with that statement), which means we start at the wall power plug and half the transient filter. The transient filter exists to mop up dirty transients that come in on the nice clean AC sine wave.

On the receptacle, we have two Y capacitors, two X capacitors, a resistor to drain the capacitors when the unit is unplugged, and a ferrite bead on both the power leads and the ground lead.

On the main PCB we see two more X capacitors, two more Y capacitors, two inductors, a fuse, and a TVS Diode for surge protection. This is a solid transient filter!

Following the transient filter are the primary rectifiers, which are followed by two Y caps and yet another X cap. The rectifiers are BU1506 units rated at 600 volts and 15 amps each, there are two of them. Just after the rectifiers is a very well hidden inrush current limiting thermistor.

Following that is the aPFC, which boost the incoming 90-264 V to something in the mid to high 300 V range and stores it in three large capacitors, two from Nippon Chemi-Con and one with ambiguous markings.

Taking clear photos of the aPFC’s MOSFETs and diode proved to be impossible, but I was able to ID them. The switching duties are handled by a pair of 6R099C6 MOSFETs rated at 650 V and 24-37.9 amps (at 100 °C and 25 °C respectively) and the diode is a STTH3006DPI unit rated at 30 amps and 600 volts.

Next in line are the main switches, a pair of 6R099 MOSFETs rated at 600 volts and 19-31 amps (again at 100 °C and 25 °C), one of these is out in the open so I could take a good picture of it! This is rare and exciting.

Then it’s through the transformer and off to the secondary rectifiers, this is a synchronous design with four 023N04N MOSFETs (40 volts, 90 amps) and two 015N04N MOSFETs (40 volts 120 amps). 600 amps for a unit with a rated 12 V output of 105 amps? This thing might be slightly overbuilt. I approve! As this unit uses DC-DC regulation for the secondary rails it puts out almost its entire capacity on the 12 V rail. We’ll get to the 5 V and 3.3 V rails shortly.

Okay, like I said above, this unit uses DC-DC regulation for the 5 V and 3.3 V rails. They come from a matching pair of daughter boards containing buck converter type regulators to drop the 12 V to 5 V and 3.3 V, below is a photo of them.

At this point, there are a few nice juicy Nippon Chemi-Con output filter capacitors, and then it’s onward to the modular output board for distribution into the outside world!

Here we see more filter capacitors, as well as soldered nuts holding the mounting standoffs to the modular output PCB. This is depressingly rare and it makes me very happy to see Cooler Master spending the extra time and money to make sure things are securely mounted.

That does it for the tour, all in all this is a very well built and very overbuilt unit.

Final Thoughts and Conclusion

Cooler Master’s Silent Pro Hybrid 1300 W power supply has done quite well, it starts off with great looks and and fully modular cables and continued to look better and better as I went through the unit.

The cables are nice to work with and easy to hide, the fully modular nature of this unit means that you won’t have to tuck unused cables into drive bays or behind things. The cables themselves are (other than the ATX24P cable) ribbon cables with a soft flexible feel to them, they are very easy to route and their flat black coloring will camouflage them well in most cases. The ATX24P cable is nicely sleeved, it is also totally symmetrical so it doesn’t matter which end you plug into the PSU. An oddity is the 3.3 V sense wire that is parallel to one of the 3.3 V wires, making it quite literally useless. Why it is even included is beyond me. The cables are all of good length, even the largest cases out there should be within reach of this PSU’s cables.

The price is solid, right in the middle of the ballpark for a unit of this size and efficiency. This makes the included fan controller a genuinely free bonus part, which is very nice.

I like the look of the unit itself quite a bit, it has a fingerprint-resisting rough black/grey finish with just a little bit of glittery stuff thrown in, it looks fantastic. The fan surround’s gunmetal grey sets it off nicely, as well.

The voltage regulation offered up by this unit was excellent, especially on the 12v rail. Ripple was well-controlled, with all results well within specification.

The build quality was almost perfect, one solder defect and a small blob of glue rattling around under the PCB put a dent in the unit’s rating there. This is quite unfortunate as it was headed towards a near-perfect result before I ran into those issues. The components used are all quite high quality and significantly over sized, I suspect this unit could do a lot more than 1300 W. Despite this, I do NOT recommend overloading any power supply. It’s a bad idea at best.

I’m very pleased to see the pair of 7 V fan power connectors, this is a feature that I don’t believe anybody else has started offering and is very useful for people who want nice quiet PCs. The fan controller works well, though full speed is only 10 V. It can drive quite juicy fans however and looks quite nice. The ability to control the PSU fan is interesting, I’m not sure it’s hugely useful but it is nice to have the option.

To summarize, there are pros:

• Nice cables, they’re easy to work with, easy to hide, and long enough for any case.
• Fully modular, all the cables can be disconnected.
• The entire unit looks excellent.
• Excellent voltage regulation.
• Excellent ripple control.
• Nicely over sized internal components.
• Build quality almost perfect.
• Fan is literally dead silent at low loads, and not loud even at full load.
• 7 V fan power plugs for running fans at 7 V without expensive controllers, inefficient resistors or dubious wiring.
• Comes with a nice looking fan controller that functions quite well and can control the PSU fan.

Nothing being perfect, there are cons too:

• One lead of one component not fully soldered.
• Small piece of non-conductive glue was rattling around under the main PCB.

Short con list, huge pro list, this unit easily gets the Overclockers.com Approved badge!

– Bobnova