XFX Pro 750W Black Edition Fully Modular Review

eTeknix has been absent from the world of power supply reviews for around 18 months. Ever since our Sunmoon ATE SM -268 Load Tester broke we have been left without enough test equipment to do a “proper” power supply review. By proper we mean not simply loading the system with VGA/CPU components and taking motherboard readings with programs like OCCT, neither do we find using a multimeter is accurate enough. Our definition of proper power supply testing at eTeknix has been to use a dedicated power supply load tester. Just a week ago we took a trip to Hamburg in Germany where Enermax kindly allowed us to test a whopping 29 power supplies on their Chroma power supply load tester.

The first of those power supplies we tested for review was the XFX Pro 750W Black Edition fully modular power supply. This power supply from XFX is actually manufactured more or less entirely by Seasonic and is based upon the Seasonic X-750. XFX is actually one of Seasonic’s OEM partners. With 750W of continuous power over a single 12 volt rail the XFX Pro 750W power supply is designed to power the most demanding gaming systems with a single ultra high performance GPU or a pair of mid-high end GPUs.

Furthermore the XFX Pro 750W Black Edition uses a fully modular design meaning it is entirely capable of giving you a clean looking system. What’s more impressive is every cable is fully black while all cables, except the motherboard 24 pin, use “flat” black cables for easier cable management. Furthermore the power supply features a hybrid fan switch that allows you to switch between an “always on” or “hybrid on/off” fan mode. The always on mode means the fan always spins and varies with temperature while the hybrid on/off mode allows the fan to turn off at low loads. The option to choose is indeed a very nice feature.

On top of all that the XFX Pro 750W Black Edition power supply is one of the most aggressively priced power supplies on the market and comes with a 5 year warranty, yet has performance that beats most of its competitors if the Seasonic X-750 is anything to go by. But without any further ado, let us proceed on to this XFX Pro 750W Black Edition power supply review and sea how this product stacks up.

Specifications and the product page for this product can be found here.

The front of the packaging details XFX’s key features. That is what it calls “solid link” technology and EasyRail Plus Technology.

The rear of the box explains SolidLink technology and EasyRail Plus technology.

SolidLink technology reduces the number of wires power and current have to flow through thus increasing efficiency and reducing heat wastage. EasyRail Plus controls all devices on a single 12 volt rail ensuring every device always has enough power.

The other side breaks down the key power specifications. You can see this PSU is capable of supplying up to 62 Amps on the 12 volt rail and with four 6+2 pin connectors you will be able to run SLI and CrossFireX.

Included with this product, excluding the main power supply unit, is a box full of the cables.

Here you can see they all use the “flat” cable design and are fully black with labelled connectors. The motherboard cable is sleeved but also fully black.

There is also a user manual included and a UK power plug. The appropriate power cable will be supplied in your country of purchase.

The XFX Pro 750W Black Edition power supply uses a 120mm fan with a custom fan grille.

It uses an entirely modular design allowing you to connect:

• An ATX 24 pin connector
• An EPS/ATX 12v 4+4 pin
• An EPS/ATX 12v 8 pin
• Four PCIe 6+2 pins
• Ten Serial ATA connectors
• Five Molex connectors
• An optional Floppy Disk Drive adapter connector (uses one of your ten Molex connectors when fitted)

The left side is quite plain with the XFX logo and product name.

The other side is also a total replica. Both sides are of the opposite orientation so whichever way you mount it puts the label facing the correct way in a conventional PC chassis.

The back features ventilation and a 3 pronged power “kettle lead” connector. There is a hard-wired on/off switch too.

The bottom is relatively plan and features the power configuration, model name and details of certifications which notably include 80 Plus Gold.

The 24 pin as mentioned is braided but features black cables, all the PCIe and CPU connectors use flat black designs.

The rest of the cables also include flat black designs. You get three SATA cables with 4/3/3 connectors to make 10 connectors and two molex cables with 3/2 to make 5 connectors. There is also that molex to FDD adaptor that few people will use but its inclusion is nice and I’m glad they have also sleeved it.

The XFX Pro 750W Black Edition is OEM produced by Seasonic and thus has a very clean internal layout.

It uses an ADDA DC Brushless 120mm fan with runs at up to 12 volts with 0.33 Amps. This uses a ball bearing fan motor. As far as I am aware this fan has a maximum operating speed of 2050 RPM.

The XFX Pro 750W Black Edition power supply uses a DC to DC converter design for the 3.3 volt and 5 volt rails.

There is a dual sided PCB design layout for enhanced cooling performance.

The internals feature large aluminium heatsinks to run cool.

The XFX Pro 750W Black Edition packs certified components capable of running at up to 105 degrees celsius.

Again you can see XFX’s implementation of a dual sided PCB design to not only enhance the quality of components they can fit in a small space but also improve airflow.

The cables are connected with an all in one DC cabling design directly onto the PCB, this reduces heat wastage. You can also see more Japanese capacitors.

At eTeknix we take the power supply testing procedure very seriously. For all power supply reviews we used a variety of Chroma machines and other digital power machinery provided by Enermax in their European test labs. We would like to say a huge thank you to Enermax for making this power supply testing possible.

The test machinery included the following:

• A Chroma 6314A power supply load tester with two add on 6314 modules to support up to six 12 volt rails.
• A Chroma Digital Power Meter Model 66202
• A Custom-made Enermax PCB circuit board to connect all the appropriate power supply cables
• A Tektronix TDS 3014C Digital Phosphor Oscilloscope
• A Voltcraft DT-10L Laser Tachometer

The eTeknix test procedure involves:

• Testing each power supply at 20/40/60/80/100% load (with balanced load across all rails) and measuring PFC (power factor correction), efficiency (actual power divided by power “pulled at the wall”) and voltage regulation (deviance from expected voltages of 3.3/5/12).
• Measuring ripple and noise with an oscilloscope at 20/40/60/80/100% load.
• Measuring voltage regulation and ripple/noise at Maximum 12v loads and maximum 3.3/5v loads while keeping the -12v and 5vsb consistently at 0.1A and 1A on the rail(s) not being tested. For example under 12v crossload we would load the 12v rail to its maximum and place 0.1A on the -12v and 5vsb as well as 1A on the 3.3v and 5v rails.
• Measuring fan speed after a stabilisation period of five minutes at each load scenario using the Voltcraft DT-10L laser tachometer and a reflective strip on the fan.

Other things to consider are that

• We recognise that a single yellow 12 volt cable can provide only 6 Amps before overheating (which corrupts voltage regulation and efficiency) and so we used an adequate number of cables for each power supply.
• Our power supply tester was capable of only 50 Amps on the 12 volt 1 rail, 50 Amps on the 12 volt 2 rail and 25 Amps on rails 3-6. This meant that for single 12 volt power supplies with rail Amps above 50 we had to split them virtually over two rails to maximise their load. There are no power supplies that we tested that have more than 50 Amps over two rails so this was only an issue for single 12 volt rail power supplies.
• We use the same time scale and horizontal millivolt scale on our oscilloscope for all noise and ripple tests.
• Deviance is the terminology used to represent the way voltages diverge from their expected values.

Voltage Regulation

To test voltage regulation we load the power supply to five different load scenarios that give an equal spread of load across every single rail. So that means 20% on all rails, 40% on all rails and so on. We then calculate the average deviance of each rail from its expected voltage.

XFX promised less than plus or minus 3% voltage deviance on each rail. We can see they actually stayed more or less within 1% voltage deviance on all rails which is an incredibly impressive achievement. The distribution of load onto a second virtual 12 volt rail at the end was done to stop the Chroma exceeding 50 amps on the 12 volt rail 1, you can find more details in the testing method page.

Power Efficiency

Power efficiency is measured by calculating actual supplied wattage divided by the wattage drawn at the wall/plug, multiplied by 100 to give a percentage. We then compare that to the particular 80 Plus certification the company claims to see if it meets that. You can see the 80 Plus certifications below, we always test 230v power supplies.

As the graph demonstrates the XFX Pro 750W power supply meets the 80 Plus Gold standard quite comfortably doing much better than required at all levels of load. It is actually surprisingly close to Platinum certification with only the 50% load being about 2% lower than it needs to be while 100% and 20% load are almost spot on.

Power Factor Correction

Power Factor Correction is the ratio of the real power flowing to the load, to the apparent power in the circuit. The aim of PFC is to make the load circuitry that is power factor corrected appear purely resistive (apparent power equal to real power). In this case, the voltage and current are in phase and the reactive power consumption is zero. The closer the number to one the better as this allows the most efficient delivery of electrical power (Source – Wikipedia).

The XFX Pro 750W Black Edition produced consistently high levels of PFC.

Noise and Ripple can easily be measured by an oscilloscope. These show how much voltage fluctuation there is on a particular rail. We tested the rail stability of the 3.3 volt, 5 volt and 12 volt rails using an identical time and millivolt scale for all graphs.

The latest ATX 12 volt version 2.3 specifications state that ripple from peak to peak must be no higher than 50 millivolts for the 3.3 volt and 5 volt rails, while the 12 volt rail is allowed up to 120 millivolts peak to peak to stay within specifications.

Load (%)	3.3V Ripple	5V Ripple	12V Ripple
20
40
60
80
100

As we can see the XFX Pro 750W Black Edition power supply had super tight regulation with very low noise and ripple across all rails. It was well within ATX specification and almost close to a total flat-line. In an ideal world there would be a totally flat-line with 0 millivolts of peak to peak ripple, the XFX unit wasn’t far off this.

Our cross loading procedure is designed to rigorously test the stability of the main two rail combinations. We push the maximum rated current and wattage through the 12 volt rail(s), and then through the 3.3 and 5 volt rails combined, and see if the power supply is capable of delivering its specification for those. However, meeting the specification is not enough, the power supply must also maintain strong voltage regulation and noise/ripple to have “passed the cross load test. 

The cross load test is a “worst case scenario” for the two main power delivery rail mechanisms (12v and 3.3+5v) and so the power supply will always deliver slightly lower than realistic/expected results. However, this is not necessarily a realistic test and it is just a case of pushing a power supply’s rails right to their rated limits to see how well they can hold up.

12 Volt Cross Loading

Voltage regulation was exceptional given the high cross loading. Only the -12v rail broke the trend and had some slightly average performance but that said the -12 volt rail isn’t that important to the overall system. The main one here is the 12 volt rail which held up exceptionally well with very low voltage deviance.

Ripple and noise was fantastic given the immense stress the 12 volt rail was placed under.

5 and 3.3 Volt Cross Loading

Voltage regulation at 5 and 3.3 volt cross load was exceptionally tight and I have no complaints here at all.

Noise and ripple on both the 3.3 volt and 5 volt rails was near zero which is always fantastic to see at cross load.

When testing in a power supply laboratory it is difficult to take fan noise readings as the noise from the Chroma corrupts everything. The next best thing in our circumstances was reading off the fan speed with a tachometer to get an idea for the noise. In the Enermax Europe PSU lab we had to do exactly that and we recorded the fan speed at each load scenario. The ambient temperature during testing held constant at 26 degrees, with 1 degree of variation. Each power supply had a consistent time period of 5 minutes to stabilise between each load scenario. 

In my experience the following general relationships apply between noise levels and fan speeds, though it can vary greatly between the type of fan used.

• Below 800 RPM – Inaudible/Silent
• 800 to 1000 RPM – Barely audible
• 1000 – 1200 RPM – Audible but still quiet
• 1200 – 1400 RPM – Moderately noisy
• 1400 – 1800 RPM – Noisy
• 1800 RPM or higher – Intolerable

The XFX Pro 750W Black Edition power supply was virtually silent the entire time running at less than 900RPM even at 100% load. This is certainly a great achievement and is testament to the efficiency of the unit as it shows very little power is wasted as excess heat. 

The XFX Pro 750W Black Edition Fully Modular Power Supply costs £114.90 in the UK. This makes the XFX power supply significantly cheaper than competitors such as the Corsair AX760i which costs around £145 and the Seasonic X-750 (the power supply this is based on) which costs £130. XFX really have worked miracles with this pricing and you wonder if they can even make a profit on them, but “business speculation” aside the XFX Pro 750W Black Edition power supply is an absolute steal at £114.90 and I can’t see any power supply out there that can possibly challenge this unit in terms of what it offers for the money.

The power supply is in my opinion totally flawless. It has incredibly tight voltage regulation at all load scenarios including cross load, the noise and ripple is non existent in virtually all scenarios and the efficiency is above its rated 80 Plus Gold certification requirements. Furthermore the PFC scores were very impressive, the power supply looks the business, the cables are beautifully braided/blackened, the fully modular design ticks a lot of boxes for most enthusiasts and the fan is totally silent at all loads with the option to switch to a hybrid on/off mode where it turns off at low loads. After all that I think it is clear that there isn’t anything to dislike about this power supply!

Pros

• Tight voltage regulation on all rails
• High efficiency, slightly higher than 80 Plus Gold
• Consistently high PFC levels
• Fan operates at low speeds at all loads and is very quiet
• Very affordable price relative to competitors
• 5 year warranty
• Hybrid Fan On/Off switch
• High quality components

Cons

• None! – I challenge you to find me one

eTeknix says: “XFX have produced one of the best high end power supplies on the market that will suit the needs of almost every single/dual GPU gamer out there. With high efficiency, high PFC, tight voltage regulation, low noise, a massive 5 year warranty and a fully modular design what’s not to like about the XFX Pro 750W Black Edition power supply? Congratulations to XFX for such a great power supply.“

XFX Pro 750W Black Edition Fully Modular Power Supply

Thank you to XFX for providing this review sample.