Corsair AX1500i Review (Power Supply)
When Corsair launched their AX1200i (and the other models in the same range) they brought to market a PSU with some very interesting features. These started with the Digital Signal Processor and continued on with a USB interface and software suite which allowed us to easily monitor our unit from within Windows. The fact that this software suite was also compatible with other Corsair products such as some of their coolers meant it was a very interesting release for enthusiasts.
Today Corsair are refreshing their AX-I range of PSUs and on our test bench we have the high end model, the 1500w AX1500i.
Packaging and Bundle
Corsair package their AX1500i in familiar packaging which gives some key information on product specs and features. Inside we find the PSU encased in foam and wrapped in protective material to ensure it arrives in pristine condition. Bundled with the unit we get the usual selection of cable ties, screws and case badge along with a wide selection of cables which include TEN 6+2 pin PCIe connectors and 20 SATA connectors. Each of the cables is flat and as with the last generation we also get the USB connector for our Corsair Link software. Here is a breakdown of all the connectors provided.
ATX 24/20 Pin
EPS 8 pin
PCI-E 6+2 pin
Before we look at the PSU itself, here is the latest revision of Corsair Link which gives us plenty of information on efficiency, power use and real time readings across the PSU lines. We can also configure fan profiles, view temperatures and configure our 12v rail.
The AX1500i PSU
Externally the AX1500i follows similar styling to the rest of the AX range, though we do get little tweaks such as the colour of the 1500i logo which points to this units 80Plus Titanium certification (120v -94%, 240v-95%). Round at the back of the PSU we get a 3-pin connector (90-264v) and rocker power switch with the rest of the surface, other than a small logo, being perforated to promote airflow out from the centre mounted fan. Swinging the PSU round we find a wide selection of modular connections, there is no native wiring here, and then up at the top left corners we see the self-test button (checks DC rails/fan) and communication ports. In terms of dimensions the AX1500i measures 150x86x225mm.
Inside the AX1500i we have a unit which, like the previous generation of this range, is based on a Flextronics design. Corsair and Flextronics call this their second generation digital architecture which means we have a Digital Signal Processor (DSP) which provides DC voltage output regulation of <+/-1.5% on the 12v rail along with ripple performance which exceeds the ATX spec by 3x. Speaking of that 12v rail, it is rated for 125A in this unit. Interestingly Corsair also note that it is possible, through the DSP and Corsair Link, for it to act like a multi-rail design by setting over-current trip points on the individual PCIe outputs.
Corsair cool the AX1500i with a single fluid dynamic bearing 14cm fan and like many of their other units is model is capable of running without the fan at low loads. So up to 30% (450w) the fan is motionless, then slowly increases with the load (from around 60%) to minimise noise even when on.
Corsair back up the high quality parts inside (such as 105°C rated Japanese capacitors, magnetic moulding, low RDS(on) Mosfets and 4-layer modular PCB with circuit trace optimisation) with Over-Voltage, Over-Current, Over-Temperature and Short-Circuit protection while also doing their qualification tests at 50°C to ensure real life reliability and stability. All of this makes them confident enough to provide a 7-year warranty on the AX1500i.
What other stand out features do Corsair offer? First up the PSU and its DSP are capable of compensating on the fly for DC output cable voltage drop. The unit also contains digital interleaved bridgeless PFC (power factor correction) and PWM control which maximise power factor performance with the lowest total harmonic distortion under all loads thanks to an optimised software algorithm. In addition the AX1500i also uses isolated interleaved fix duty half bridge LLC convertors on the 12V/5V rails as well as DC to DC for the 3.3v rail… and those MOSFETs we mentioned earlier, some of those replace the AC input diode bridge rectifier.
|Corsair 1500W AXi Power Supply|
|Max Combined Wattage||180W||1500W||9.6W||17.5W|
|1500 Watts @ 50°C ambient temperature|
As Corsair are introducing their second generation digital architecture on the AX1500i it gets the benefits of a couple of years worth of experience, testing and real world feedback from the likes of the AX1200i. When we combine this with the already impressive base unit from that older model and the use of high quality components in this unit (right down to a decent level of solder quality) the revised AX1500i becomes a stand out model in the PSU marketplace. It is hard to pick fault on a hardware level, maybe the use of a small USB connector for the Link cable isn’t ideal (something sturdier would be preferred) but that’s about it. On the software side things still are not ideal though, for example it can be a bit quirky on first boot/idle in terms of readings given but usually settles down after any sort of period at load. It is fairly responsive, though a bit clunky, but has pretty much every feature we could need.
When running the AX1500i the first thing that becomes obvious is the low noise. In real world use even with the likes of a high end i7-4960X and the R9-295X running we idled in fanless mode which is great. A period of gaming see’s the fan kick in but the RPM stays low and it is only when we apply a significant overclock and additional GPUs that the RPM kicks in to a noticeable about. That said, the fan used here produces minimal noise and runs far quieter than the average liquid cooler and GPU cooler. Interestingly we did note during our lab testing, rather than real world, that the return to fanless mode did take a little longer than we would have expected, a few minutes at least. Elsewhere the temperature levels were more than acceptable however we did feel the rails were a little loose at low loads but under any sort of stress performance picked up and the AX1500i delivered rock solid performance along with some very nice ripple results. Efficiency did hit the Titanium specification in our test environment which was a nice bonus and as a side note, thinking back to that i7-OC/295X2 real world system, with 3 drives, the liquid cooler, peripherals, 16GB of memory and wifi all connected we were hitting approximately 50% load on the PSU when gaming. So peak efficiency when gaming from this unit.
So that’s it for our initial limited time testing the AX1500i, it will be interesting to see how it performs in some extended testing and should it fluctuate we will update our performance figures. In terms of value though it should come as no surprise that the AX1500i has a hefty price tag and that is unlikely to change any time soon. The level of component inside and the overall design/functionality all combine to create this $449 RRP and that significant price tag is softened a little by 7-year warranty.
Building an enthusiast/ultra-high end system? Then quite simply this is the PSU for you.
|Where to buy…|
|Corsair – £449.99|
|Corsair – $449.99|