Corsair HX1500i (Gen 4 2025) Power Supply Review

1. Introduction2. Bundle & Cabling3. External4. Internal5. Testing Methodology and Results6. Closing Thoughts7. View All Pages

3 years have passed since my review of the HX1500i power supply and today we take a look at the updated 4th Generation unit for 2025. These new units are Platinum Certified, fully modular and are clearly targeting the high end audience rocking an RTX 5090 or similar graphics card. Corsair are offering two models, a 1200W and a 1500W – the latter of which we are reviewing today.

As well as a new modified design, Corsair have updated the 2025 model with braided cables with low profile combs and the PSU ships with dual 12V-2×6 cables.

Both of these new 4th Generation HXi power supplies have achieved the excellent Cybenetics Platinum certification – which is a much more important certification than the dated 80 Plus platform. Both supplies are ATX 3.1 and PCIe 5.1 ready and feature a 140mm Fluid Dynamic Bearing fan as well as 105c rated Japanese capacitors. Corsair are offering a full 10 year warranty with both of these new power supplies.

If you don't know already, the ‘i' in the product name means they support iCUE (Corsair Software) so you can get full Digital control through the desktop software.

This software allows you to override the default settings and create custom fan profiles as well as monitoring power settings. You can also use the software to switch between single or multi rail overcurrent protection (OCP). Corsair are working with Channel Well Technology (CWT) as the OEM manufacturer of these power supplies, in partnership with their own engineering team behind the scenes.

Includes:

• Compatible with next-gen GPUs
• Dual 12V-2×6 cables
• Fluid Dynamic Bearing fan with Zero RPM mode
• 105°C rated 100% Japanese electrolytic capacitors
• 10-year warranty
• Intel® ATX 3.1 certified, PCIe 5.1 compatible

The HX1500i ships in a distinctive bright yellow box with key information on the front, such as the Cybenetics Platinum Certification, ATX 3.1/PCIe 5.1 compatibility, the iCue capabilities, 10 year warranty and support for the latest Nvidia 50 series graphics cards.

The rear of the box highlights other features such as Zero RPM fan mode, the dimensions and some graphs on efficiency and noise levels.

Inside, the box is split into two sections. The power supply is shipped sandwiched between two blocks of cardboard. The cables and accessories are in a black box taking up half the space on the right side.

As you would expect with a high end 1500 watt power supply, Corsair include a wide variety of high quality cables to cover every eventuality. The cables predominately are 16-18 AWG. None of them have in cable capacitors.

The PSU is nicely finished and looks pretty much identical to the one we reviewed back in July 2022. This is a large power supply measuring 150mm x 82mm x 200mm so will not be an ideal candidate for space restricted chassis designs.

The branding of the unit is clean and simple – with the product name and ‘Corsair' highlighted in a simple white colour.

One side is home the power connector and fan switch, along with the vented panel. This unit takes a high power C19 cable, which is included in the box. What is a C19 cable? they are designed to deal with higher levels of power – you can see in the image above the 3 power prongs are longer and flat. The C19 power connector is bigger and robust, with a rectangular shape and 2x rows of pins, typically four in total. This design allows the C19 connector to handle a higher maximum current.

The HX1500i can deliver 25A across the +3.3V and +5V rails. The primary +12V rail can handle a whopping 125A – which is considerable.

The HXi power supply is supported by Corsair iCUE software, although you really don't need to use it at all. As you will see later in the review, Corsair have pretty much nailed the fan profile at default settings.

That said, if you do want to give it a whirl, simply connect the USB C cable to the power supply and the motherboard. Launch iCUE and make sure you are running the latest updated version. From the home screen you then select HXi. From here you can adjust Fan Curves to create your own cooling presets. Sensor tiles are at the right and they can be moved around. You can also switch between Single Rail OCP and Multi Rail OCP in the software.

Corsair are using a NR140P Fluid Dynamic Bearing fan. This is rated 12V DC 0.22A. You can buy these fans for around the £20 mark HERE. So they are quite expensive. This is the same fan we saw in our reviews of earlier generations years ago, and even the plastic surround to focus air flow over specific parts of the internals is identical.

Don't fix what isn't broken I say – the NR140P is a superb fan.

The primary side of this unit is full bridge topology – it has an APFC and a LLC resonant converter. On the secondary side a synchronous rectification scheme is used for 12V with a pair of DC to DC converters generating the minor rails. It has been created for Corsair by CWT under their guidance.

The soldering and build quality is at a level we would expect for a flagship model. The unit is clean and well designed throughout. If you pay attention you can see two mains transformers were used beside each other instead of a single larger on. This helps reduce the demand for space.

The PCB is large which helps with cooling efficiency. Corsair and CWT have opted for smaller heatsinks due to the physical dimensions and rated Platinum levels of efficiency. On the secondary side the 12V FETs are installed on a vertical board.

There are three 105c rated Japanese Nippon Chemi Con Capacitors in the HX1500i from their KMZ series. Two are rated 450V 680uF and the third is a little smaller rated 420V 470uF. This gives a total of 1830uF.

The unit ships with OVP, OCP, SCP, OPP and OTP protections.

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
• Extech digital sound level meter
• Digital oscilloscope (20M S/s with 12 Bit ADC)
• Variable Autotransformer, 1.4 KVA

12V output is single rail for our testing.

DC Output Load Regulation
Combined DC Load	+3.3V		+5V		+12V		+5VSB		-12V
	A	V	A	V	A	V	A	V	A	V
150W	0.90	3.34	0.84	5.03	11.65	12.06	0.5	5.01	0.20	-12.01
300W	1.63	3.34	1.65	5.03	23.75	12.05	1.0	5.01	0.20	-12.01
750W	3.01	3.34	3.02	5.03	59.66	12.03	1.5	5.01	0.30	-12.01
1125W	4.05	3.34	4.05	5.03	90.00	12.02	2.0	5.01	0.30	-12.01
1500W	15.56	3.33	15.55	5.02	113.30	12.01	2.5	5.01	0.50	-12.01

Load regulation is very tight on all the rails. Excellent set of results.

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
1150W	3.0	3.34	2.0	5.03	92.0	12.02	0.2	-12.02	0.50	5.01
250W	20.0	3.33	24.0	5.02	5.0	12.05	0.2	-12.01	0.50	5.01

The power supply did very well in our Cross Load tests, indicating a very stable design.

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 it is (less ripple 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
500W	10	8	9	6
750W	11	11	11	8
1000W	12	14	13	9
1250W	14	18	18	10
1500W	16	19	24	11

Ripple results are excellent, falling within the top 10% of units tested.

Efficiency (%)
500W	93.21
750W	94.41
1000W	93.66
1250W	92.76
1500W	91.88

The efficiency ratings are excellent, peaking around 94.5% between 45-50% and dropping to 91.9% at full load.

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)
500W	<28.0
750W	30.4
1000W	32.7
1250W	34.9
1500W	36.1

The power supply remains quiet at sub 1,000 watt demands and once demand exceeds 1,100 watts the fan starts to spin up to compensate for rising temperatures inside. At full load the PSU is clearly audible but never too intrusive. It is a very quiet power supply overall with a very relaxed fan profile in place, aided by the overall high efficiency levels throughout.

We didn't record any coil whine either throughout the range of power delivery.

Temperature (c)
	Intake	Exhaust
500W	36	38
750W	38	40
1000W	40	44
1250W	42	51
1500W	44	55

Due to the high efficiency level of this unit, it never runs hot, even when delivering huge amounts of power. These are a very good set of results.

The latest 4th Generation of the HX1500i builds on the previous models and brings it into 2025 with the latest support for ATX 3.1 and PCIe 5.1. Corsair continue to work with CWT on the design of the new 1200 watt and 1500 watt supplies in this HXi range and many things carry over, such as the adoption of the excellent NR140P Fluid Dynamic Bearing fan.

Technically there is a lot to praise with the latest design. Ripple suppression is excellent and in the top 10% of all units we have tested in recent years.  Efficiency is stellar, hitting over 94% at around 50% load. Load regulation is very tight and we like the fact that the unit has a wide array of protection features sometimes missing on other high end power supplies.

One of the key selling points of this power supply is the low noise, smooth power delivery operation, even at loads up to 1200 watts. It was almost inaudible to my ear in a quiet room from a few meters distance, and even at full load remained relatively quiet. I am a big fan (pun intended) of Corsair's NR140P Fluid Dynamic Bearing fan used in this and previous HXi power supplies. It is one of my favourites. These fans are quite expensive and I have bought some before myself for other projects (around £20 a fan). As a side note, one of the NR140P fans I own has been running in a server now for 4 years – 24 hours a day without any issues (I usually clean it once a year).

Temperatures inside the power supply remain cool under even high load situations thanks to the high levels of efficiency and excellent performance of the aforementioned NR140P. Build quality throughout is exceptional and Corsair have not skimped on quality capacitors, using some of the highest grade Japanese Nippon Chemi Con caps from their KMZ Series. The three primary caps combined can deliver a staggering 1830uF output.

As you would expect, a power supply of this calibre does not come cheap, and it is priced at £299.99 from Corsair's own store HERE. Similar prices can be found across main etailers in the UK, so it falls into the high end of supplies. In reality it is one of the best we have tested, so it justifies the price point. Just be sure you are definitely buying the current Gen 4 version as some of the older versions are still popping up on etailers as we go live with this review.

Pros:

• Delivers a sustained 1,500 watts without a problem.
• 10 year warranty.
• Highest grade 105c rated Japanese Nippon Chemi Con capacitors.
• Extremely efficient.
• High quality cables.
• Very quiet, even at high loads.
• Excellent default fan profile.
• Tight Load Regulation.
• Fully modular.
• iCUE support (but you don't need to use it as default settings are great).
• ATX 3.1 and PCIe 5.1 compliant.
• Super High Grade FDB fan (the NR140P is one of my favourites).
• Expensive, but not super expensive like some we have reviewed lately around £500.

Cons:

• It is not cheap, as you would expect.
• It is physically large.

KitGuru says: The HX1500i is one of the finest, quietest high end power supplies on the market. Corsair have built this unit to the highest standards and have adopted some of the finest quality components inside to ensure long life and smooth power delivery. It is one of the best power supplies we have tested to date and while expensive – compared to others we have tested recently at £500, it offers great value for money.

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