NZXT C1500 Platinum PSU review: Plenty of efficient power

NZXT, founded in 2004, is a prominent American computer hardware manufacturer known for its range of products including computer cases, cooling solutions, power supplies, and accessories. Headquartered in Los Angeles, California, the company targets the gaming and enthusiast market with innovative designs and practical solutions. Their product lineup features a blend of aesthetics and functionality, catering to the needs of PC builders and gamers seeking high performance and reliability.

In this review, we are examining the latest addition to NZXT's power supply lineup, the C1500 Platinum PSU, which currently goes for $370. This high-capacity power supply offers exceptional performance and reliability for modern, top-tier PCs. With features like fully modular black nylon-sleeved cables, a Sunon MagLev 140 mm fan, two PCI Express 5.1 12V-2x6, and boasting world-class electrical performance, the C1500 Platinum is designed to meet ATX 3.1 standards and get the attention of enthusiasts and power users who are on the market for one of the best power supplies currently available.

Specifications and Design

In the Box

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The NZXT C1500 Platinum PSU comes in straightforward yet efficient packaging. The outer box features a purple-white theme, dominated by a picture of the unit itself. The PSU is well-protected during shipping by a nylon pouch and dense packaging foam, ensuring the safety of the product during transportation.

Considering the tier of this PSU, its bundle is surprisingly minimalistic. NZXT provides only the necessary mounting screws, an IEC C19 AC power cable, and a purple bag for the modular cables. The package is spartan, providing only the essential accessories needed for installation.

The NZXT C1500 Platinum PSU features all-black cables, including connectors and wires, all covered in black nylon sleeving, giving the unit a sleek and uniform appearance. The highlight here is the presence of two 600 Watts 12V-2x6 connectors and six PCI Express 6+2 pin cables with just one connector on each, forgoing “piggybagging” multiple PCI Express connectors on a single cable.

External Appearance

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The NZXT C1500 Platinum PSU is housed in a chassis that measures 180 mm in length, significantly longer than the standard ATX dimensions specified by the ATX design guide. This extra length is unsurprising bearing in mind its high-power output and requires a case with ample clearance to fit properly. It features a sleek and understated design, with a smooth satin black finish. 

It avoids unnecessary decorations, instead displaying discreetly etched company and series logos on the sides for a clean appearance. The top side is labeled with a sticker that details the electrical specifications and certifications. The unit features a unique fan guard with a square design and honeycomb cutouts, combining effective protection from the fan but also enhances the unit's overall aesthetic with its distinct design.

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The front side of the NZXT C1500 Platinum PSU features the standard on/off switch, the IEC C20 AC cable receptacle, and an additional switch for the "Zero-Fan" feature. The switch allows users to disable the feature and force the fan to operate continuously regardless of the unit’s load or temperature but the speed of the fan will still be controlled by the unit’s thermal control circuitry, so it will be practically be running at minimum speed until the load is high enough to justify an airflow increase.

The rear of the unit is littered with modular cable connectors, which are keyed in order to prevent mishaps. The connectors are not color-coded and the legend is barely visible but it is not possible to actually install any cable into the wrong connector.

Internal Design

The NZXT C1500 Platinum PSU is equipped with a Sunon MagLev MFE0251VX-1Q010-S99 140 mm fan, featuring a magnetic levitation engine. The patented Sunon engine design offers superior performance and also the fan's performance is not affected by orientation. This type of fan is known for its superior performance and durability, making it a judicious choice for a top-tier PSU. While MagLev fans can be noisy at higher speeds, they excel in high-temperature environments. The fan in this model can reach the terrifying maximum speed of 2500 RPM – hopefully, it will not have to.

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The NZXT C1500 Platinum ATX 3.1 PSU is produced by Channel-Well Technology (CWT), a Taiwanese OEM with extensive experience in the power supply industry. CWT has a long history of designing and manufacturing mid-to-top-tier PC power supplies, known for their quality and reliability. They are behind many of the latest high-performance units from various reputable brands, including this NZXT model.

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This platform does not bring ground-breaking changes into the power electronics world but it is a step up from most other readily available designs available right now. While the core design of the unit is based on well-established topologies, the designer replaced some of the analog sensors with digital ones, which have massively better response times and allow for tuning flexibility. The input stage features a robust filtering setup, consisting of four Y capacitors, two X capacitors, and two filtering inductors, which then feed two rectifying bridges (WNR2560M). The bridges are sharing the heatsink with the Active Power Factor Correction (APFC) active components, which are two APFC MOSFETs and two diodes. The passive components of the APFC circuit are two large encased inductors and three massive Rubycon 820 μF capacitors.

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The primary inversion stage of the NZXT C1500 Platinum employs four Alpha & Omega TF29S50 MOSFETs forming a full-bridge inversion circuit. All four MOSFETs are mounted on a single heatsink dedicated to them. The primary stage is feeding two transformers that, in turn, feed the two secondary stage conversion circuit vertical daughterboards that generate the primary 12V line. 

It is a synchronous rectification setup and a total of sixteen Infineon 014N06NS MOSFETs are being used. The 3.3V and 5V rails are produced via DC-to-DC conversion on a vertical daughterboard. The capacitors on the secondary side, electrolytics and polymer alike, are all from reputable Japanese manufacturers (Rubycon, Nichicon, and Nippon Chemi-Con).

Cold Test Results

Cold Test Results (25°C Ambient)

For the testing of PSUs, we are using high precision electronic loads with a maximum power draw of 2700 Watts, a Rigol DS5042M 40 MHz oscilloscope, an Extech 380803 power analyzer, two high precision UNI-T UT-325 digital thermometers, an Extech HD600 SPL meter, a self-designed hotbox and various other bits and parts.

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The NZXT C1500 Platinum PSU easily meets the 80Plus Platinum certification standards, missing the 80Plus Titanium certification by a hair when tested with an input voltage of 115 VAC. When tested with a 115 VAC input, it achieves an average nominal load efficiency of 92.6%, which increases to 93.7% with a 230 VAC input. The unit's efficiency peaks at around 40% of its capacity. Additionally, the PSU demonstrates impressive efficiency even at low loads, nearing 87% with a load of just 70 Watts.

The NZXT C1500 Platinum PSU features a "Zero-Fan" mode, keeping the fan off during low-load conditions to maintain quiet operation. In our testing, the fan began to operate slightly before the unit was at 50% capacity, which means that the C1500 Platinum essentially operated fanless until the load was greater than 700 Watts. NZXT’s marketing graph show that the fan starts when the unit is at around 60% capacity, which may be achievable under ideal laboratory conditions. As the load exceeds 50%, the fan increases its speed to manage the rising thermal output, slowly at first but more sharply when the load goes above 1200 Watts, yet it never reaches its maximum speed under these testing conditions.

Hot Test Results

Hot Test Results (~45°C Ambient)

During hot testing, the NZXT C1500 Platinum PSU displays a very minor decrease in efficiency under heavy loads, with recorded figures of 92.2% at 115 VAC and 93.3% at 230 VAC, compared to 92.6% and 93.7% during cold testing. This reduction is inconsequential and occurs almost linearly across the entire load range. There are no signs of thermal stress, even at maximum load. The PSU is rated to perform efficiently at ambient temperatures up to 50°C and maintains seamless operation under these conditions.

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Under hot testing conditions, the NZXT C1500 Platinum PSU's fan activates a little earlier but its speed does not increase significantly before the load is greater than 850 Watts, after which point the speed of the fan increases sharply. This approach keeps noise levels acceptable with a load up to 800 Watts. 

When heavily stressed, the thermal control circuit seems to be designed so as to forgo acoustics performance in favor of reliability. The internal temperatures of the unit are remarkably low, especially when taking the massive 1.5 kW capacity into account.

PSU Quality and Bottom Line

Power Supply Quality

The electrical performance of the NZXT C1500 Platinum PSU, even after taking into account its class, can only be described as outstanding. The 12V rail maintains a tight regulation of 0.5%, while the 5V and 3.3V lines are well-regulated at 0.7% and 0.6% respectively.

Ripple suppression is equally impressive, with low values of 24 mV for the 12V line, 12 mV for the 5V line, and 14 mV for the 3.3V line. These figures were taken with a load of 1.5 kW, which makes them even more impressive considering that most modern designs struggle to reach such performance at half that wattage.

During our thorough assessment, we evaluate the essential protection features of every power supply unit we review, including Over Current Protection (OCP), Over Voltage Protection (OVP), Over Power Protection (OPP), and Short Circuit Protection (SCP). The NZXT C1500 Platinum PSU successfully passed all critical protection tests, confirming its capability to protect both the PSU and connected components. 

The unit displayed standard OCP settings for the 3.3V and 5V rails, activating at 116% and 118% respectively, which are typical for these specifications. The 12V rail’s OCP activation at 122% is slightly higher but still is very sharp for an ATX 3.1 unit and that is a very good thing considering its massive capacity.

Bottom Line

The NZXT C1500 Platinum PSU stands out as a robust and high-performance power supply unit tailored for extreme gaming PCs and workstations. With its impressive power output of 1500 Watts, it comfortably supports the most demanding components currently on the market. The sleek design, featuring a smooth satin black finish and discreetly etched logos, as well as the unique square honeycomb fan guard, add a touch of elegance - but NZXT’s design focus clearly was not aesthetics. This PSU was designed with raw overall performance above everything else.

One of the key features of the NZXT C1500 Platinum is its advanced cooling fan. The 140 mm Sunon MagLev fan, equipped with a magnetic levitation engine, ensures superior cooling performance and durability. The fan remains off during low-load conditions, thanks to the "Zero-Fan" mode, which keeps the system quiet under typical usage scenarios. 

When the load exceeds approximately 50%, the fan activates to manage thermal output effectively but will not reach disturbingly high noise output levels. During hot testing, the fan starts a bit sooner but will still maintain civil noise levels until the load is greater than 1 kW, after which point the unit will prioritize cooling over noise reduction. The internal temperatures of the C1500 Platinum are, under any testing conditions, very low even for a unit with that high an efficiency.

The electrical performance of the NZXT C1500 Platinum is equally impressive. It showcases excellent voltage regulation and world-class ripple suppression, with values that other designs cannot reach at half this unit’s capacity. The unit's efficiency is very high, achieving 92.6% at 115 VAC and 93.7% at 230 VAC during cold testing, missing the 80Plus Titanium certification by a hair during 115 VAC testing (93.8% at 50% load). Even under hot testing conditions, the efficiency drop is minimal, ensuring reliable performance across a wide range of operating temperatures.

The NZXT C1500 Platinum PSU excels in protection and build quality. Manufactured by Channel-Well Technology (CWT), a reputable OEM, the unit features top-tier Japanese capacitors from Rubycon, Nichicon, and Nippon Chemi-Con. Its solid construction and high-quality components are backed by a 10-year warranty, providing users with peace of mind. However, its steep  price tag is a significant drawback. This substantial cost positions it in a niche market, appealing primarily to the few extreme users who require its massive 1500W power output. For many users, the performance may not justify the premium price, especially when comparable alternatives existing at lower price points. 

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