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Over recent weeks we have reviewed the XFX Pro Series 650w and 750W power supplies and today we finish our series of reviews by looking at the highest wattage version in the non modular Pro series – the 850W model.
The Pro Series power supplies are designed to be cost effective, quality units for the enthusiast who doesn't want to spend significantly more for 80 Plus Gold efficiency. Being 80 Plus Bronze certified, they still offer high levels of efficiency while remaining affordable. The 850W model on test today is only £90 inc vat right now in the UK.
EasyRail Technology is a key focal point for XFX with a slogan of ‘one rail, one setup’. We know that Seasonic are the manufacturer behind this design so we have high hopes for a quality power supply today. XFX are giving a full five year warranty with each power supply. European customers simply have to register their product on www.xfxforce.co.uk to upgrade the standard 3 year warranty to the full 5 year plan.
The new XFX packaging looks fantastic, hinting immediately at the inclusion of a high quality product inside.
The shipping protection is first class. After removing the outer sleeve there is an inner box with a stylish pixelised box art design. The top layer contains a manual, sandwiched between two holders cut into the cardboard. Underneath is the power supply.
XFX bundle both European and UK power cables with a set of screws to mount into your case.
This range is not modular by design, so all the cables are wrapped within a heavy duty cable tie.
The XFX Pro Series all share the same rugged, heavy duty enclosure with angular panels. The centre of the fan proudly displays the XFX logo. The rear is home to the ventilation which XFX are calling the “Ultra Ventilation (Grid Structure) system”. This is to allow for maximum air flow for improved cooling with lower noise levels.
| XFX Pro Series 850W Power Supply | |||||
|
DC Output
|
+3.3V
|
+5V
|
+12V
|
-12V
|
+5Vsb
|
|
Max Output
|
25A
|
25A
|
70A
|
0.5A
|
3A
|
|
Max Combined
|
150W
|
840W
|
6W
|
15W
|
|
| Cables | |
| 24/20 Pin | x1 fixed |
| CPU 4+4 Pin | x1 fixed |
| CPU 8 Pin | x1 fixed |
| PCI-E 6+2pin | x2 fixed |
| PCI-E 6 pin | x2 fixed |
| SATA | x11 fixed |
| HDD | x8 fixed |
| FDD | x1 fixed |
The cables are fully sleeved and very high quailty.
The Power supply is cooled by a 135x135x135 mm fan (Adda ADN512UB-A90). The impeller is a nice design, nine wide blades with small gaps between.
The XFX power supply is manufactured by Seasonic and it is a very clean internal design. This is a DC to DC Converter Design to provide enhanced Dynamic response while ensuring system stability and maximum 12VDC rail output.
There are several rows of heatsinks, seperating the components and ensuring adequate airflow from the large fan directly above. The XFX PSU is supplied with automatic output protection to ensure no damage occurs. This includes Total Power Protection (OPP), Over Voltage Protection (OVP), Over Current Protection (OCP), Short Circuit Protection (SCP) and Over Temperature Protection (OTP).
XFX are using high quality Japanese brand capacitors rated to withstand up to 105c. These are conductive Polymer Aluminum Solid Electrolytic Capacitors to help improve operational stability under continued load conditions.
The cables are sleeved well into the chassis, which helps to ensure no long term damage by fraying. The cabling is well routed and organised with ties.
Additional technical assistance: Peter McFarland and Jeremy Price.
Correctly testing power supplies is a complex procedure and KitGuru have configured a test bench which can deliver up to a 2,000 watt DC load. Due to public requests we have changed our temperature settings recently – previously we rated with ambient temperatures at 25C, we have increased ambient temperatures by 10c (to 35c) in our environment to greater reflect warmer internal chassis conditions.
We use combinations of the following hardware:
• SunMoon SM-268
• CSI3710A Programmable DC load (+3.3V and +5V outputs)
• CSI3711A Programmable DC load (+12V1, +12V2, +12V3, and +12V4)
• Extech Power Analyzer
• Extech MultiMaster MM570 digital multimeter
• SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa)
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA
|
DC Output Load Regulation
|
||||||||||
|
Combined DC Load |
+3.3V
|
+5V
|
+12V
|
+5VSB
|
-12V | |||||
|
A
|
V
|
A
|
V
|
A
|
V
|
A
|
V
|
A | V | |
|
100W
|
1.58
|
3.34
|
1.78
|
5.03
|
6.65
|
12.08
|
0.50
|
5.05
|
0.20
|
-12.08
|
|
225W
|
3.70
|
3.34
|
3.85
|
5.02
|
15.54
|
12.07
|
1.00
|
5.03
|
0.20
|
-12.07
|
|
450W
|
7.51
|
3.33
|
8.40
|
5.02
|
30.67
|
12.06
|
1.50
|
5.02
|
0.30
|
-12.05
|
| 675W |
11.32
|
3.32
|
12.41
|
5.01
|
47.48
|
12.03
|
2.00
|
5.01 |
0.50
|
-12.03
|
|
850W
|
1.29
|
3.30
|
1.11
|
5.00
|
71.00
|
12.00
|
0.50
|
4.99
|
0.20
|
-12.01
|
The Pro 850W delivered excellent load regulation on all output channels across a wide range of loads. These are fantastic results and the +3.3V and 5V rails remained firmly within +/-2% of the nominal voltage instead of the recommended +/-5% and the +12V rail held within +/- 1%, even when it was forced to deliver over 70 Amps.
| XFX Pro Series 850W | Maximum Load |
| 923.8W |
We managed to coax 923.8W from the supply before it shut down gracefully. It was able to maintain a 900W output for a long period of time. The overcircuit protection system is working perfectly. It shut down until we acted more sensibly with our equipment.
Next we want to try Cross Loading. This basically means loads which are not balanced. If a PC for instance needs 500W on the +12V outputs but something like 30W via the combined 3.3V and +5V outputs then the voltage regulation can fluctuate badly.
| Cross Load Testing | +3.3V | +5V | +12V | -12V | +5VSB | |||||
| A | V | A | V | A | V | A | V | A | V | |
| 760W | 1.0 | 3.34 | 1.0 | 5.03 | 65.0 | 12.07 | 0.2 | -12.08 | 0.50 | 5.02 |
| 165W | 15.0 | 3.28 | 18.0 | 4.98 | 2.0 | 12.02 | 0.2 | -12.02 | 0.50 | 5.01 |
The XFX Pro Series 850W handled the cross loading tests very well with only very minor levels of fluctuation under load.
We then used an oscilloscope to measure AC ripple and noise present on the DC outputs. We set the oscilloscope time base to check for AC ripple at both high and low ends of the spectrum.
ATX12V V2.2 specification for DC output ripple and noise is defined in the ATX 12V power supply design guide.
|
ATX12V Ver 2.2 Noise/Ripple Tolerance
|
|
|
Output
|
Ripple (mV p-p)
|
|
+3.3V
|
50
|
|
+5V
|
50
|
|
+12V1
|
120
|
|
+12V2
|
120
|
|
-12V
|
120
|
|
+5VSB
|
50
|
Obviously when measuring AC noise and ripple on the DC outputs the cleaner (less recorded) means we have a better end result. We measured this AC signal amplitude to see how closely the XFX unit complied with the ATX standard.
| AC Ripple (mV p-p) | ||||
| DC Load | +3.3V | +5V | +12V | 5VSB |
| 100W | 5 | 5 | 5 | 5 |
| 225W | 5 | 5 | 10 | 5 |
| 450W | 5 | 5 | 15 | 10 |
| 675W | 10 | 10 | 15 | 15 |
| 850W | 10 | 10 | 20 | 15 |
Ripple results are well within the parameters set down in the ATX12V Ver 2.2 standard. +3.3V and +5V are extremely impressive and the +12V rail is also very stable, peaking at 20mv. This is the best result from the three XFX Pro series PSU's we have tested to date.
|
Efficiency (%)
|
|
|
100W
|
85.41
|
|
225W
|
86.89
|
|
450W
|
87.84
|
|
675W
|
85.21
|
|
850W
|
83.91
|
These efficiency results are great for a 80 Plus Bronze certified supply, hitting 87.84% at around 50% load. At full load the efficiency drops to just under 84%, which is very impressive.
We take the issue of noise very seriously at KitGuru and this is why we have built a special home brew system as a reference point when we test noise levels of various components. Why do this? Well this means we can eliminate secondary noise pollution in the test room and concentrate on components we are testing. It also brings us slightly closer to industry standards, such as DIN 45635.
Today to test the Power Supply we have taken it into our acoustics room environment and have set our SkyTronic DSL 2 Digital Sound Level Meter (6-130dBa) one meter away from the unit. We have no other fans running so we can effectively measure just the noise from the unit itself.
As this can be a little confusing for people, here are various dBa ratings in with real world situations to help describe the various levels.
KitGuru noise guide
10dBA – Normal Breathing/Rustling Leaves
20-25dBA – Whisper
30dBA – High Quality Computer fan
40dBA – A Bubbling Brook, or a Refridgerator
50dBA – Normal Conversation
60dBA – Laughter
70dBA – Vacuum Cleaner or Hairdryer
80dBA – City Traffic or a Garbage Disposal
90dBA – Motorcycle or Lawnmower
100dBA – MP3 Player at maximum output
110dBA – Orchestra
120dBA – Front row rock concert/Jet Engine
130dBA – Threshold of Pain
140dBA – Military Jet takeoff/Gunshot (close range)
160dBA – Instant Perforation of eardrum
|
Noise (dBA)
|
|
|
100W
|
27.1
|
|
225W
|
29.1
|
|
450W
|
29.9
|
|
675W
|
32.8
|
| 850W | 34.8 |
Our noise results are (not surprisingly) very close to the XFX Pro Series 750W PSU we reviewed last week. At around 70% load, the PSU become audible, rising to a maximum of 34.8 dBa at 100% load. It isn’t the world’s quietest PSU by a long shot, but at realistic load levels it should not annoy the user base.
|
Temperature (c)
|
||
|
Intake
|
Exhaust
|
|
|
100W
|
35
|
37
|
|
225W
|
35
|
38
|
|
450W
|
38
|
42
|
|
675W
|
42
|
52
|
|
850W
|
45
|
54
|
The large fan pushes a lot of airflow under load which helps to keep the components in check. At around 70-80% load, the fan speeds start increasing considerably. At full load we reach a 9c above ambient intake threshold.
|
Maximum load
|
Efficiency
|
|
923.8W
|
81.2
|
Pushing the PSU above its rated limits generates an efficiency level of around 81.2%. This is not a viable ‘real world’ situation, but its interesting nonetheless.
The XFX 850W Pro Series Power Supply certainly has not failed to impress, it combines a great design ethic with rock solid build quality. Of the three supplies in this particular range (850W, 750W, 650W), it maintains the lowest ripple results and delivers the highest efficiency levels, by a small margin.
The Seasonic design displays very balanced results across all our testing with no problems or inherent weaknesses. As a 80 Plus Bronze certified unit it is pretty much as good as it gets. Noise levels are acceptable and the large fan is capable of ensuring good airflow even when under full, sustained load.
The XFX Pro Series 850W is one of the finest value for money high performance units on the market … retailing for £90 inc vat, it is sure to find its way into many demanding gaming systems over the next couple of months.
KitGuru says: The 850W Pro Series unit combines great performance characteristics and high efficiency at a very reasonable price.
