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Today we look at one of Corsairs latest power supplies, and one that sits right at the top end of the efficiency spectrum – their new AX850 80+ unit. This replaces their older Gold rated model which I reviewed way back in August 2010. This new model pushes efficiency boundaries to the limit for the consumer market – shipping with a Titanium (96%) efficiency rating.
The AX range of units sits high in the Corsair stable and the Titanium rating comes at a cost – this 850 watt model retails for a staggering £215 in the United Kingdom right now (buy from OCUK HERE).
Like the SF750 supply which we reviewed very recently (HERE) Corsair are focusing on reducing noise emissions as far as they can so they have equipped this particular unit with a 135mm Fluid dynamic bearing fan.
Corsair say their FDB fans are a higher standard than most, as they use rifling on the inside and outside of the bearing, as well on the spindle. This ensures proper distribution of lubrication throughout the bearing and an MTBF greater than 100,000 hours. We will look at the noise levels later in this review.
It is worth pointing out that this is not one of Corsair's ‘i' series power supplies, so you won't be able to use utilities such as Corsair iCue software for monitoring, but for many people this won't be a deal breaker.
Specifications
- AC Input Rating 100-240V
- Input Current 11A – 5.5A
- FDB Fan bearing
- MTBF: 100,000 hours
- PSU Form Factor: ATX
- Link Compatibility: NO
- Frequency 50 ~ 60 Hz
- Max Load Max Output
- +3.3V 100W
- +5V 100W
- +12V 840W
- +5Vsb 15 W
- 10 year warranty
We like the new Corsair box artwork, with major key points listed along the front of the box, and a high resolution image taking centerstage in the middle.
Corsair like to get a bit more technical on the back of the box. If you feel the need to read it all. We wonder if anyone does! The power supply is wrapped in a nice little bag for added protection inside the box.
The box includes quite a good bundle with the power supply. Corsair give you three replaceable (magnetic) badges for the sides, in case you want to get creative with your colour matching. They also include a regional specific power connector, felt and plastic cable ties and literature on the unit. There is also a pouch containing all the modular cables.
You ‘roll open' the cable pouch – its lovely presentation. Each section of the pouch is labelled to help with the installation phase of the build. The quality of the cables is good, but they are not unfortunately individual sleeved, like we saw with the SF750 which we reviewed over HERE. Those are some cool cables.
Connectors:
– 1 x 24-pin ATX Cable
– 2 x EPS12V/ATX12V Cable (4+4)
– 6 x PCIe Cable (6+2)
– 8 x SATA
– 6 x Molex
– 1 x Floppy
The Corsair power supply is ATX, and is 170 mm x 86 mm x 150 mm in diameter. Its nicely finished and seems fairly resistant to scratches and finger prints.
The 135mm fan is hidden behind a metal grill on the top of the power supply. We will get a closer look at this shortly.
There is a large sticker on one side of the case which explains the ‘Zero RPM' fan mode. As we always say, less noise is always good.
When the sticker is removed, we can see the power connector, power switch and the ‘zero noise' fan button. You can disable it to have the fan active at all times, if you want of course. Perhaps useful in a very warm climate or a case that has restricted airflow.
One side of the power supply is home to the modular drive bay which is clearly labelled and to help with routing during the build phase.
| Corsair AX850 80+ Titanium Power Supply | |||||
|
DC Output
|
+3.3V
|
+5V
|
+12V |
-12V
|
+5Vsb
|
|
Max Output
|
20A
|
20A
|
70A |
0.3A
|
3A
|
| Total Power | 100W | 840W | 3.6W | 15W | |
| 850W | |||||
The single +12V rail is able to deliver 7 amps which is plenty for any Crossfire or SLI system build I can imagine. The minor rails deliver 20A.
Inside the Corsair AX850, we are greeted to a Hong Hua 135mm Fluid Dynamic Bearing fan (Model: HA13525L12F-Z). This is a quality fan we have seen in some high end units in previous months including many Prime units from Seasonic. the fan is rated for 0.22A and 1600 rpm at 12 VDC. It is generally a quiet fan. It is built for long life and quiet operation.
Below - a High Resolution Gallery of the internal layout of the Power supply.
If you can’t see the image gallery above then you will likely need to white list us in your ad blocker as they are known to interfere with our display code.
The internal design of this unit is very clean and the soldering quality is top drawer. All the electrolytic capacitors inside are Japanese made, which is always good to see. The primary bulk capacitors are made by Japanese giant Nippon Chemi Con and are rated 400v 680uf and 400v 470uF. They are from their KMR series rated 105C. This gives a total output of 1150uF which on paper means this unit is very capable of delivering a lot of power – especially for an 850W rated unit.
Secondary capacitors are all Japanese and we can see a diode bridge for AC DC rectification of the incoming AC voltage. All in all this is a really clean, effective design for such a high efficiency unit.
We notice that even though this unit is Titanium rated and clearly highly efficient, Corsair have populated the PCB with 4 or 5 heatsinks in key positions – just to ensure heat gets removed in situations with little, to no airflow.
It has OCP, OVP, UVP, SCP, OTP and OPP protection in place.
We tested the unit to see if it exhibited coil whine, and even under very heavy load conditions and when playing games at lower resolutions running at 300fps we couldn't exacerbate any problems.
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. We run at 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
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA
We test in a single +12V configuration.
|
DC Output Load Regulation
|
||||||||||
|
Combined DC Load |
+3.3V
|
+5V
|
+12V
|
+5VSB
|
-12V | |||||
|
A
|
V
|
A
|
V
|
A
|
V
|
A
|
V
|
A | V | |
|
85W
|
0.95
|
3.34
|
0.92
|
5.01
|
6.00
|
12.01
|
0.50
|
5.03
|
0.20 | -12.01 |
|
170W
|
1.70
|
3.34
|
1.67
|
5.01
|
12.35
|
12.00
|
1.00
|
5.03
|
0.20 | -12.01 |
|
425W
|
3.00
|
3.33
|
3.05
|
5.01
|
32.20
|
12.00
|
1.50
|
5.02
|
0.30 | -12.01 |
| 640W | 4.05 | 3.33 | 4.05 | 5.00 | 49.00 | 12.00 | 2.00 | 5.02 | 0.30 | -12.01 |
|
850W
|
5.00
|
3.33
|
5.23
|
5.00
|
65.52
|
11.98
|
2.50
|
5.01
|
0.50 | -12.02 |
Load regulation is very strong with the rails holding with 1% of recommended specifications.
| Corsair AX850 80+ Titanium Power Supply | Maximum Load |
| 995W |
We managed to get the power supply to deliver 995W before it would shut down, delivering around 145W more than rated specifications.
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 | 3.33 | 1.0 | 5.01 | 60.0 | 11.99 | 0.2 | -12.01 | 0.50 | 5.02 |
| 165W | 15.0 | 3.32 | 18.0 | 4.99 | 2.0 | 12.01 | 0.2 | -12.02 | 0.50 | 5.01 |
The power supply dealt with the demanding cross load test very well exhibiting little fluctuation. It was tasked with 60A on the +12V rail and it held at 11.99W. The other rails delivered excellent results also.
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 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 | 10 | 5 |
| 675W | 5 | 10 | 15 | 10 |
| 850W | 5 | 10 | 15 | 10 |
Noise suppression is stellar, and top of the class, peaking at 5mV and 10mV from the +3.3V and 5V rails respectively. The +12V rail peaks at 15mV. Great results all round.
|
Efficiency (%) 240V
|
|
|
100W
|
91.67
|
|
225W
|
94.83
|
|
450W
|
96.70
|
|
675W
|
95.88
|
| 850W | 94.72 |
Efficiency is yet again top of the field, peaking at around 96.5% at close to 50% load. At full load this drops to around 94.52%.
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 Digital Sound Level Noise Decibel Meter Style 2 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 Refrigerator
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
|
<28.0
|
|
225W
|
<28.0
|
|
450W
|
<28.0
|
|
675W
|
31.7
|
| 850W | 33.2 |
This is one of the quietest power supplies we have tested in the last couple of years. Below 500W the fans didn't seem to spin at all, and above 500W load then it kicked a little into action. At 600Watts the fan spins up a little, although it would still be classed as ‘whisper quiet'. This highlights the efficiency of the Titanium unit. At 850W, under full load conditions the fan was spinning at around 800 RPM (according to our equipment), and the noise levels were still barely audible.
If you are in the market for an extremely quiet power supply – look no further.
|
Temperature (c)
|
||
|
Intake
|
Exhaust
|
|
|
100W
|
37
|
38
|
|
225W
|
38
|
41
|
|
450W
|
39
|
45
|
|
675W
|
43
|
48
|
|
850W
|
45
|
51
|
The fan may hardly spin at all, but again the efficiency of the Titanium design reaps dividends. The power supply runs cool at all times. Even at full load, the results are incredible.
|
Maximum load
|
Efficiency
|
|
995 watts
|
94.2
|
At 995 watts, this unit managed to deliver efficiency just over 94%. Incredible!
The Corsair AX850 80+ Titanium Power Supply is one of the most efficient power supplies we have ever tested at KitGuru. At optimum delivery it delivers efficiency of 96.7% – putting it into the top units we have tested.
Technically this is another great AX product – load regulation is rock solid, and ripple suppression is class leading. The adoption of Fluid Dynamic bearing fan with Zero RPM means that this is a quiet power supply, even under high load situations. Even at full load the noise emissions were cloaked by a single case fan. It also handled the demanding cross load test without an issue.
While it is not unique to this particular power supply, the option to have an ‘always on' fan will appeal to a specific audience running in a very hot environment or perhaps inside a case with very limited airflow. The high levels of efficiency and quality of internal design ensure that this is a cool running power supply, even when tasked with higher levels of load demand.
Internally Corsair haven't cut corners, and they have adopted high grade 105c Japanese capacitors throughout the build – from brands such as Nippon Chemi Con. Even though efficiency levels reach 96.7%, Corsair have included multiple small heatsinks across the PCB to ensure key components cool adequately with minimal, or no airflow.
Modders out there will appreciate the colour options available on the side panels, with a standard grey logo included, along with black/white, red and blue. I appreciate the cost involved but I would have liked to see the cables come individually sleeved, even if it meant adding a little more to the overall cost of the unit.
I guess Corsair want people purchasing their premium cable kits but at the price point this power supply is targeted the audience just want the best (performing and looking) product they can get, so charging a little extra for individually sleeved cables in the box might have been a good option.
You can buy the Corsair AX850 Titanium Plus power supply from Overclockers UK for £214.99 inc vat HERE
Pros:
- Built to very high standards.
- Class leading efficiency.
- superb ripple suppression.
- load regulation is rock solid.
- colour options are welcome.
- 10 year warranty.
- very quiet, even under load.
- delivered almost 1000 watts.
- Primary capacitors are hugely over-specified.
Cons:
- It's expensive.
- individually sleeved cables would be nice.
KitGuru says: This is another powerhouse power supply from Corsair. The Corsair AX850 Titanium costs a lot of money, but if you want the highest quality power from a unit that exhibits little noise even under full load, this surely has to be right at the top of your list. The included magnetic stickers are a nice extra.
