The AX650, like the AX750 and AX850 PSUs, is based on Seasonic's
flagship platform which the Seasonic X series units also utilize.
Briefly, the AX650 uses a fully modular cable design which as we see
will dominate in the years to come, has 80 Plus Gold efficiency and
features a dedicated single +12V rail. Also its compact dimensions
render it compatible with all normal PC chassis and the exclusive use of
Japan made caps along with the ball bearings fan ensure a long,
trouble-free lifespan. On top of that Corsairs offers a seven year
warranty to all AX units ensuring this way the long peace of mind of all
future buyers. But enough with the long talk, let's skip to the main
review and see what the AX650 really has to offer and how it stands
against the competition.
Specifications
Efficiency is Gold and unfortunately the same goes for its price too. At $150 it's one of the most expensive 650W PSUs in the market. The PSU can deliver its full power even at 50°C ambient, the only protections missing are OPP (Over Power Protection) and the relatively rare OTP (Over Temperature Protection), the fan is equipped with ball bearings for extended lifespan and its footprint is small. Finally, someone surely cannot miss the seven year warranty that Corsair offers with this unit (and all AX PSUs as well). Such a long warranty period provides the ultimate peace of mind to the future buyer.
There is only one +12V rail which can deliver the unit's full power, something very convenient since all modern systems draw power mainly from this rail. The minor rails have more than satisfactory power and the 5VSB rail is strong enough with 3A max power.
Cables & Connectors, Power Distribution
The PSU utilizes a fully modular cabling design and all cables are fully
sleeved, except the peripheral/SATA connectors which use ribbon cables.
Unfortunately Corsair/Seasonic considered that two EPS connectors in a
650W PSU would be too much so they equipped the AX650 with only one EPS
connector. However there are four PCIe connectors along with many SATA
and peripheral connectors. Strangely enough the number of peripheral
connectors is equal to the SATA ones and this is odd because less and
less components nowadays use peripheral connectors. In general all
cables are long enough and the distance among the connectors is
adequate. Finally all connectors use 18AWG which is the recommended, by
ATX spec, wire size.
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Since this PSU features a single +12V rail we do not have anything to comment about its power distribution.
Packaging
The box that contains the unit is quite large, especially if we take
into account the PSU's compact size. In general the package is similar
to the ones of the other AX units. On the front we find an angled photo
of the modular panel along with the model number of the PSU, in the
bottom right corner. The small Gold efficiency badge along with the
badge for the seven year warranty can be found right under the model
description. If you want to learn more about the available
cables/connectors and the unit's features and specifications then you
should take a look at the rear side of the box. There you will find two
interesting graphs, one for the output noise and one for the unit's
efficiency. In the first of the afore-mentioned graphs we can see that
the PSU goes fanless at low loads. Actually the fanless operation is
more temperature related than load related, meaning that if the PSU is
running cold at low ambient then it will operate in fanless mode even if
the load is high. On the contrary if it is quite hot and the ambient is
high then the fan will engage even at low loads (<130W). This is of
course the best thing to do since following this pattern the components
of the unit are not stressed by high operating temperatures.
Contents
The internals of the box are protected really well by two thick layers
of packaging foam. On top of that the unit comes inside a plastic bag
and is stored in a luxury cloth bag. We are talking about full
protection here. In a nylon pouch you can find the modular cables along
with a small bag containing several zip ties and a Corsair badge. The
rest of the bundle includes a user's manual which is common for all AX
units, an AC power cord and a set of fixing bolts.
Exterior
As we already stated the unit's dimensions are restricted, something
that of course is a benefit since it will easily fit in most cases. The
finish is of high quality, fairly scratch resistant but not so
fingerprint proof. On the front there is the classic honeycomb style
vent and next to the AC receptacle resides an On/Off switch. On the two
sides the decals are rather simplistic and serious but after all the
name of the AX series includes the word "Professional". The power
specifications label is located on the unit's bottom side so it won't
bother the modders. On the rear side we meet the modular panel which
does not feature any labels or at least colors for sockets
identification. Thankfully it is dead easy to find the right socket for
each cable so you can't go wrong here. Finally, the 120mm fan is
protected by a simple fan grill which features Corsair's logo on its
center.
A Look Inside
Before reading this page we strongly suggest to take a look at this article, which will help you understand the internal components of a PSU much better.
As we already stated, the OEM of this unit is Seasonic, one of the best
PSU manufacturers with huge experience and long history in this field.
On the main PCB we do not find any large heatsinks, since energy
dissipation is kept low thanks to the high efficiency and on top of that
the case itself plays a crucial role in cooling down the secondary side
mosfets. In order to decrease the amount of wires that transfer DC
voltages inside the unit, thus minimize energy losses, the DC-DC
converters are housed on the modular PCB and the modular sockets that
are fed exclusively by +12V are soldered directly on the main PCB. This
why the main 24pin ATX connector from the PSU side consists of two
smaller connectors.
The AC receptacle incorporates a complete line filter from Yunpen (YO-T1 series) which includes one X and two Y caps and two chokes. On its terminals we also find another X cap. The remaining components of the transient filter, two CM chokes, one X and two caps and an MOV reside on the main PCB. Right next to the MOV there is an NTC thermistor responsible for protection against large inrush currents and an electromagnetic relay which isolates the thermistor from the circuit once the start up phase finishes, increasing efficiency this way.
There are two GBJ 1506 bridge rectifiers, bolted on a dedicated heatsink. These bridges are way two strong for the unit's mere 650W capacity. In front of them an X cap is soldered; its job is to filter the high frequency ripple.
In the APFC three IPP60R190C6 mosfets are used along with a CREE C3D06060 boost diode. The two parallel hold up caps are provided by Nippon Chemi-Con (330µF each or 660µF combined, 420V, 105°C, KMR series). In order to boost efficiency an LLC converter is utilized.
The main choppers are two IPP60R190C6 fets and the resonant controller is a CM6901 IC. The latter is soldered on a vertical, leaned, PCB.
The standby PWM controller is an ICE2QR4765 and is soldered on the component side of the main PCB.
In the secondary side there isn't any heatsink holding the +12V mosfets, just some smaller heatsinks with wide fins and six polymer caps underneath of them. The mosfets, four IPD036N04L, that rectify +12V are located on the solder side of the main PCB and are cooled passively by the case itself and the three afore-mentioned heatsinks on the PCB's components side. All electrolytic caps in the secondary side are provided by Chemi-Con and Rubycon, a killer combination.
The VRMs responsible for the minor rails' generation are located on the modular PCB. There we find an APW7159 PWM controller and in total eight IPD060N03L mosfets. On the front of the modular PCB we find two small chokes and several polymer caps.
The protections IC is housed on a vertical daughter-board and is a PS223 IC. This IC supports the rare Over Temperature Protection and provides OCP for up to two +12V rails.
The AC receptacle incorporates a complete line filter from Yunpen (YO-T1 series) which includes one X and two Y caps and two chokes. On its terminals we also find another X cap. The remaining components of the transient filter, two CM chokes, one X and two caps and an MOV reside on the main PCB. Right next to the MOV there is an NTC thermistor responsible for protection against large inrush currents and an electromagnetic relay which isolates the thermistor from the circuit once the start up phase finishes, increasing efficiency this way.
There are two GBJ 1506 bridge rectifiers, bolted on a dedicated heatsink. These bridges are way two strong for the unit's mere 650W capacity. In front of them an X cap is soldered; its job is to filter the high frequency ripple.
In the APFC three IPP60R190C6 mosfets are used along with a CREE C3D06060 boost diode. The two parallel hold up caps are provided by Nippon Chemi-Con (330µF each or 660µF combined, 420V, 105°C, KMR series). In order to boost efficiency an LLC converter is utilized.
The main choppers are two IPP60R190C6 fets and the resonant controller is a CM6901 IC. The latter is soldered on a vertical, leaned, PCB.
The standby PWM controller is an ICE2QR4765 and is soldered on the component side of the main PCB.
In the secondary side there isn't any heatsink holding the +12V mosfets, just some smaller heatsinks with wide fins and six polymer caps underneath of them. The mosfets, four IPD036N04L, that rectify +12V are located on the solder side of the main PCB and are cooled passively by the case itself and the three afore-mentioned heatsinks on the PCB's components side. All electrolytic caps in the secondary side are provided by Chemi-Con and Rubycon, a killer combination.
The VRMs responsible for the minor rails' generation are located on the modular PCB. There we find an APW7159 PWM controller and in total eight IPD060N03L mosfets. On the front of the modular PCB we find two small chokes and several polymer caps.
The protections IC is housed on a vertical daughter-board and is a PS223 IC. This IC supports the rare Over Temperature Protection and provides OCP for up to two +12V rails.
Soldering quality on the main PCB is typical Seasonic, very good with nice and clean solder jobs everywhere.
The cooling fan is provided by Sanyo Denki and its model number is
9S1212F404. It uses ball bearings for increased life span and at full
speed it makes its present felt. Thankfully in this unit the fan profile
is rather peaceful and on top of that at low loads/ambient the unit
operates in fanless mode.
Test Setup
All measurements are performed utilizing ten electronic loads (seven Array 3711A, 300W each, and three Array 3710A, 150W each), which are able to deliver over 2500W of load and are controlled by a custom made software. We also use a Picoscope 3424 oscilloscope, a CHY 502 thermometer, a Fluke 175 multimeter and an Instek GPM-8212 power meter. Furthermore, in our setup we have included a wooden box, which along with a heating element is used as a Hot Box. Finally, we have at our disposal four more oscilloscopes (Rigol 1052E and VS5042, Stingray DS1M12 and a second Picoscope 3424) and a CEM DT-8852 sound level meter. In this article you will find more details about our equipment and the review methodology we follow. Finally, if the manufacturer states that the maximum operating temperature of the test unit is only 40°C then we try to stay near this temperature, otherwise we crank up the heat inside the hotbox up to 45-50°C.Voltage Regulation Charts
The following charts show the voltage values of the main rails, recorded over a range from 60W to the maximum specified load, and the deviation (in percent) for the same load range.
5VSB Regulation Chart
The following chart shows how the 5VSB rail deals with the load we throw at it.
Efficiency Chart
In this chart you will find the efficiency of AX650 at low loads and at loads equal to 20-100% of PSU's maximum rated load.
Voltage Regulation and Efficiency Measurements
The first set of tests reveals the stability of voltage rails and the efficiency of AX650. The applied load equals to (approximately) 20%, 40%, 50%, 60%, 80% and 100%, of the maximum load that the PSU can handle. In addition, we conduct two more tests. In the first we stress the two minor rails (5V & 3.3V) with a high load, while the load at +12V is only 2A and in the second test we dial the maximum load that +12V can handle while load at minor rails is minimal.| Voltage Regulation & Efficiency Testing Data Corsair CMPSU-650AX | ||||||||
|---|---|---|---|---|---|---|---|---|
| Test | 12 V | 5 V | 3.3 V | 5VSB | Power (DC/AC) | Efficiency | Temp (In/Out) | PF/AC Volts |
| 20% Load | 8.915A | 1.992A | 1.959A | 0.985A | 130.00W | 88.08% | 39.9°C | 0.884 |
| 12.160V | 5.020V | 3.368V | 5.073V | 147.60W | 41.1°C | 229.9V | ||
| 40% Load | 18.211A | 4.012A | 3.953A | 1.188A | 260.00W | 90.78% | 42.1°C | 0.947 |
| 12.125V | 4.984V | 3.339V | 5.047V | 286.40W | 44.2°C | 229.8V | ||
| 50% Load | 22.769A | 5.034A | 4.965A | 1.593A | 325.00W | 90.97% | 43.6°C | 0.960 |
| 12.100V | 4.966V | 3.323V | 5.020V | 357.25W | 46.2°C | 230.1V | ||
| 60% Load | 27.334A | 6.063A | 5.987A | 2.000A | 390.00W | 90.74% | 45.7°C | 0.966 |
| 12.080V | 4.948V | 3.307V | 5.002V | 429.80W | 48.8°C | 229.3V | ||
| 80% Load | 36.696A | 8.126A | 8.059A | 2.413A | 520.00W | 90.20% | 47.4°C | 0.974 |
| 12.034V | 4.922V | 3.276V | 4.975V | 576.50W | 51.2°C | 229.2V | ||
| 100% Load | 46.735A | 9.193A | 9.124A | 3.047A | 650.00W | 89.41% | 50.2°C | 0.979 |
| 11.989V | 4.895V | 3.255V | 4.922V | 727.00W | 54.5°C | 230.0V | ||
| Crossload 1 | 2.006A | 15.011A | 15.000A | 0.500A | 148.20W | 82.29% | 45.9°C | 0.903 |
| 12.183V | 4.859V | 3.219V | 5.073V | 180.10W | 48.6°C | 230.7V | ||
| Crossload 2 | 53.995A | 1.000A | 1.000A | 1.000A | 659.60W | 90.05% | 50.9°C | 0.979 |
| 11.968V | 4.993V | 3.348V | 5.047V | 732.50W | 55.1°C | 230.3V | ||
Efficiency overall is pretty high, although with 20% load it is not up to the level we expected from a Gold efficiency PSU. Voltage regulation at +12V is below 2%, at 5V easily stays within 3% and at 3.3V it's 3.5%. Overall we were left satisfied by the unit's voltage regulation. Despite the fact that the AX650 operates in fanless mode at lower loads, inside our hotbox the fan was working from test#1 with 20% load. Until 40% load the fan was inaudible but with 50% load and at 43.6°C ambient its speed increased so it surely made its presence felt, however it wasn't annoyingly loud. At 100% load and at CL2 test the unit clearly proved that it has no problem delivering its full power even at above 50°C operating temperature. In fact the AX650 features a very cool operation and we had to leave the heating element inside our hotbox switched on for quite some time, in order to heat the PSU.
Efficiency at Low Loads
In the next tests, we measure the efficiency of AX650 at loads much lower than 20% of its maximum rated load (the lowest load that the 80 Plus Standard measures). The loads that we dial are 40, 60, 80 and 100W (for PSUs with over 500W capacity). This is important for scenarios in which a typical office PC is in idle with power saving turned on.| Efficiency at Low Loads Corsair CMPSU-650AX | |||||||
|---|---|---|---|---|---|---|---|
| Test # | 12 V | 5 V | 3.3 V | 5 VSB | Power (DC/AC) | Efficiency | PF/AC Volts |
| 1 | 1.835A | 1.992A | 1.956A | 0.195A | 40.00W | 76.85% | 0.734 |
| 12.209V | 5.020V | 3.374V | 5.127V | 52.05W | 231.2V | ||
| 2 | 3.396A | 1.992A | 1.957A | 0.392A | 60.00W | 82.14% | 0.783 |
| 12.191V | 5.020V | 3.373V | 5.100V | 73.05W | 231.0V | ||
| 3 | 4.955A | 1.992A | 1.957A | 0.589A | 80.00W | 84.61% | 0.822 |
| 12.189V | 5.020V | 3.372V | 5.100V | 94.55W | 230.8V | ||
| 4 | 6.514A | 1.992A | 1.958A | 0.786A | 100.00W | 86.13% | 0.853 |
| 12.189V | 5.020V | 3.371V | 5.087V | 116.10W | 230.6V | ||
As we expected, efficiency at low loads is pretty high. This is why we strongly advice to use a mid-wattage PSU if you want to power a system with medium power demands. You will have significant gains in power consumption at idle and lower loads, where bigger PSUs simply cannot compete with smaller capacity ones. In this case, in three out of the four tests we ran, efficiency was way above 80%, a remarkable performance.
5VSB Efficiency
ATX spec states that the 5VSB standby supply's efficiency should be as high as possible and recommends 50% or higher efficiency with 100mA load, 60% or higher with 250mA load and 70% or higher with 1A or more load.We will take four measurements, three at 100 / 250 / 1000 mA and one with the full load that 5VSB rail can handle.
| 5VSB Efficiency Corsair CMPSU-650AX | ||||
|---|---|---|---|---|
| Test # | 5VSB | Power (DC/AC) | Efficiency | PF/AC Volts |
| 1 | 0.100A | 0.51W | 62.20% | 0.053 |
| 5.136V | 0.82W | 231.6V | ||
| 2 | 0.250A | 1.28W | 73.14% | 0.109 |
| 5.136V | 1.75W | 231.6V | ||
| 3 | 1.000A | 5.08W | 78.03% | 0.317 |
| 5.082V | 6.51W | 231.6V | ||
| 4 | 3.000A | 14.95W | 78.31% | 0.492 |
| 4.984V | 19.09W | 231.6V | ||
At 5VSB, efficiency is at high levels and even at test#2 it stays above 70%, a very high reading for this amount of load (0.25A). It peaks close to 78% with the max power that the 5VSB rail can deliver.
Power Consumption in Idle & Standby
In the table below you will find the power consumption and the voltage values of all rails (except -12V), when the PSU is in idle mode (On but without any load at its rails) and the power consumption when the PSU is in standby (without any load at 5VSB).| Idle / Standby Corsair CMPSU-650AX | ||||||
|---|---|---|---|---|---|---|
| Mode | 12 V | 5 V | 3.3 V | 5VSB | Power (AC) | PF/AC Volts |
| Idle | 12.208V | 5.038V | 3.399V | 5.118V | 6.12W | 0.283 |
| 231.5V | ||||||
| Standby | 0.10W | 0.006 | ||||
| 231.6V | ||||||
Vampire power is really low, at 0.1W, so the unit easily meets the requirements of ErP Lot 2010. Apparently the standby PWM controller does a fine job restricting power consumption at standby, at minimum levels.
Cross Load Tests
For the generation of the following charts we set our loaders in auto mode, through our custom software, and try over a thousand possible load combinations with +12V, 5V and 3.3V rails. The voltage regulation deviations in each of the below charts are calculated taking the nominal values of the rails (12V, 5V and 3.3V) as point zero. We should note here that we will run this test only with PSUs that have capacity equal or lower than 1000W since it takes way too long and as the capacity increases the completion time increases exponentially.+12V Voltage Regulation Chart
5V Voltage Regulation Chart
3.3V Voltage Regulation Chart
Efficiency Chart
+12V Ripple Chart
5V Ripple Chart
3.3V Ripple Chart
5VSB Ripple Chart
Advanced Transient Response Tests
In these tests we monitor the
response of the PSU in two different scenarios. First a transient load
(11A at +12V, 5A at 5V, 6A at 3.3V and 0.5A at 5VSB) is applied for 50
ms to the PSU, while the latter is working at a 20% load state. In the
second scenario the PSU, while working with 50% load, is hit by the same
transient load. In both tests, we measure the voltage drops that the
transient load causes, using our oscilloscope. In any case voltages
should remain within the regulation limits specified by the ATX
specification. We must stress here, that the above tests are crucial,
since they simulate transient loads that a PSU is very likely to handle
(e.g. starting of a RAID array, an instant 100% load of CPU/VGAs etc.)
We call these tests “Advanced Transient Response Tests” and they are
designed to be very tough to master, especially for PSUs with capacities
lower than 500W.
| Advanced Transient Response 20% | ||||
|---|---|---|---|---|
| Voltage | Before | After | Change | Pass/Fail |
| 12 V | 12.164V | 12.019V | 1.19% | Pass |
| 5 V | 5.011V | 4.911V | 2.00% | Pass |
| 3.3 V | 3.369V | 3.257V | 3.32% | Pass |
| 5VSB | 5.082V | 4.982V | 1.97% | Pass |
| Advanced Transient Response 50% | ||||
|---|---|---|---|---|
| Voltage | Before | After | Change | Pass/Fail |
| 12 V | 12.095V | 11.940V | 1.28% | Pass |
| 5 V | 4.966V | 4.866V | 2.01% | Pass |
| 3.3 V | 3.323V | 3.214V | 3.28% | Pass |
| 5VSB | 5.029V | 4.930V | 3.02% | Pass |
Overall the registered voltage drops in these tests are well controlled
and at all times far from the respective limits. The most significant
rail, +12V, stayed close to 1% deviation, a fairly good result
especially if we take into account the unit's capacity while the minor
rails didn't pass 3.5% deviation, at worst case.
Below you will find the oscilloscope screenshots that we took during Advanced Transient Response Testing.
Below you will find the oscilloscope screenshots that we took during Advanced Transient Response Testing.
Transient Response at 20% Load
Transient Response at 50% Load
Turn-On Transient Tests
In the next set of tests we measure the
response of the PSU in simpler scenarios of transient loads, during the
turn on phase of the PSU. In the first test we turn off the PSU, dial 2A
load at 5VSB and then switch on the PSU. In the second test, while the
PSU is in standby, we dial the maximum load that +12V can handle and we
start the PSU. In the last test, while the PSU is completely switched
off (we cut off power or switch off the PSU's On/Off switch), we dial
the maximum load that +12V can handle and then we switch on the PSU from
the loader and we restore power. The ATX specification states that
recorded spikes on all rails should not exceed 10% of their nominal
values (e.g. +10% for 12V is 13.2V and for 5V is 5.5V).
In these tests we didn't notice any visible voltage overshoots and the
rise time in all three tests was within the range that ATX spec
specifies (0.2-20ms). So the final verdict is that the AX650 performed
simply excellent here.
Ripple Measurements
In the following table you will find the ripple levels that we measured on the main rails of AX650. According to ATX specification the limits are 120 mV (+12V) and 50 mV (5V, 3.3V and 5VSB).| Ripple Measurements Corsair CMPSU-650AX | |||||
|---|---|---|---|---|---|
| Test | 12 V | 5 V | 3.3 V | 5VSB | Pass/Fail |
| 20% Load | 5.6 mV | 9.7 mV | 6.7 mV | 18.7 mV | Pass |
| 40% Load | 18.8 mV | 10.4 mV | 7.1 mV | 4.2 mV | Pass |
| 50% Load | 17.1 mV | 10.6 mV | 8.0 mV | 4.9 mV | Pass |
| 60% Load | 15.6 mV | 10.9 mV | 8.0 mV | 5.8 mV | Pass |
| 80% Load | 14.5 mV | 13.7 mV | 8.2 mV | 6.9 mV | Pass |
| 100% Load | 14.9 mV | 14.8 mV | 8.7 mV | 7.7 mV | Pass |
| Crossload 1 | 25.8 mV | 13.5 mV | 7.7 mV | 18.4 mV | Pass |
| Crossload 2 | 15.2 mV | 10.3 mV | 7.0 mV | 24.4 mV | Pass |
Ripple suppression is excellent, as we expected from a Seasonic product. As you can see with 40% load ripple peaks at +12V and afterwards it starts to decrease. Most likely this weird behavior has to do with the PWM operation at lower loads while at higher loads the main choppers operate in FM mode. Also with 20% load ripple at 5VSB is high, compared to the readings of this rail at the other tests of course since 18.7mV of ripple cannot be classified as high, but afterwards it drops dead low. Overall the AX650 delivers very clean DC outputs.
Ripple at Full Load
In the following oscilloscope screenshots
you can see the AC ripple and noise that the main rails registered
(+12V, 5V, 3.3V and 5VSB). The bigger the fluctuations on the
oscilloscope's screen the bigger the ripple/noise. For all measurements
we set 0.01 V/Div (each vertical division/box equals to 0.01V) as
standard.
Ripple at Crossload 1
Ripple at Crossload 2
Performance Rating
The following graph shows the total
performance rating of the PSU in comparison with other units we have
tested before. To be more specific the tested unit is shown as 100% and
all other units' performance are relative to it. If you want take a look
at the exact method we use to calculate the performance rating of each
PSU then read this article.
Performance per Dollar
For most of you probably the following
graph will be the most interesting, since it shows how much it will set
you back the performance of the PSU you want to buy. We looked up the
current USD price of each PSU on the popular online shop Newegg and used
it along with the relative performance numbers to calculate the
Performance per Dollar Index. In case Newegg doesn't stock a specific
unit then we search for it at other popular online shops (Tigerdirect,
Amazon) and finally if the unit is not sold in the U.S. we search in
popular EU shops (e.g. Caseking) and we convert its price to dollars.
Note in the following graph all numbers are normalized by the rated
power of each PSU.
Value and Conclusion
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For starters the price of Corsair's AX650 is very high and puts it in a
difficult position especially if we compare it with another strong
mid-wattage competitor, the excellent Kingwin LZP-550
which recently received a major price cut and came down to $130.
However the latter is available only in the US (in the rest of the world
you will find it as SuperFlower Golden King 550W but with limited
availability) and is backed by only a three year warranty. The Corsair
AX650 enjoys a high availability, is backed by a seven year warranty and
Corsair is widely known for their excellent RMA. In addition the
performance of the AX650 definitely puts it in the high-end category
since it features excellent ripple suppression, good voltage regulation
and very high efficiency over the whole load range. Also the fanless
operation at low loads/ambient, the fully modular design and the quiet
fan at normal operation add more points.
source: www.techpowerup.com
