The Corsair HX850 is a high-performance power supply that delivers excellent efficiency and silent operation, particularly at low loads thanks to its ZeroRPM mode. Tom's Hardware praised its ability to maintain full power at 46°C and noted its superior noise reduction compared to competitors like the EVGA 850 G3 and Seasonic FOCUS PLUS. KitGuru highlighted its 80 Plus Platinum certification, fully modular design, and robust build quality. However, reviewers noted some drawbacks including OCP issues at 5VSB and bulky cable configurations. This PSU is ideal for enthusiasts seeking reliable, quiet power delivery but may not suit users prioritizing minimal cable clutter.
Full review
Design and Build Quality
Corsair's HX850 Platinum power supply presents a robust build quality that reflects the company's commitment to durability and performance. The power supply features a sleek black finish with a distinctive Corsair badge and a large white fan positioned behind a metal grill on the top. Tom's Hardware noted that the unit incorporates a 135mm fluid dynamic bearing fan that operates silently under normal conditions, and the design includes a Zero RPM mode that allows the fan to remain completely still at low loads, contributing to its exceptional quiet operation. KitGuru's Allan 'Zardon' Campbell emphasized the high build quality and the use of 105°C rated Japanese capacitors, which contribute to the unit's longevity and reliability.
The HX850's modular design is a standout feature, offering fully modular cables including ATX, EPS, PCIe, SATA, and peripheral connectors. This allows for cleaner cable management and better airflow within the case. The cables are a mix of sleeved (PCIe/CPU/ATX) and ribbon style (peripherals), with Type 4 cables featuring additional sense wires that improve voltage regulation. The switchable single/multiple +12V rail mode provides flexibility for different system configurations, and the inclusion of a 10-year warranty underscores Corsair's confidence in the product's reliability.
Performance and Efficiency
In terms of performance, the Corsair HX850 Platinum delivers excellent efficiency ratings, achieving 80 PLUS Platinum certification with up to 90% energy efficiency under real-world load conditions. PC Perspective's testing revealed that the unit maintained excellent voltage regulation across all outputs, with the three main outputs staying within ±2% of recommended guidelines, which is considered very good. The power supply's ability to maintain stable voltage under load conditions is crucial for system stability, especially in high-end gaming and overclocking setups. According to the same review, the HX850 demonstrated exceptional performance in DC load regulation tests, with the +12V outputs remaining well within acceptable tolerance levels even under maximum load conditions.
Efficiency testing by PC Perspective showed that the HX850 maintained high efficiency ratings across various load conditions, which is essential for reducing power waste and heat generation. The unit's active PFC with a PF value of 0.99 ensures that it meets high standards for power factor correction, contributing to overall system efficiency. Legit Reviews' testing confirmed that the HX850's efficiency was consistent and reliable, with minimal power loss during operation. Additionally, the unit's ability to operate silently under low loads thanks to its Zero RPM mode makes it ideal for quiet gaming environments.
Noise and Thermal Performance
One of the most notable aspects of the Corsair HX850 is its exceptional noise performance, which has been consistently praised across multiple reviews. Tom's Hardware highlighted that the HX850 offers 'dead silent operation under all conditions,' with the 135mm fluid dynamic bearing fan only spinning up when needed. The Zero RPM mode allows the fan to remain completely still at low loads, which is particularly beneficial for quiet gaming setups. According to KitGuru's review, the HX850's fan only spins up as needed, providing outstanding noise reduction. PC Perspective's testing confirmed that the unit maintained very low noise levels even under full load, with the fan operating at minimal RPM during light usage.
Thermal performance was also evaluated by PC Perspective, which found that the HX850 maintained stable temperatures under various load conditions. The power supply's ability to operate efficiently at 46°C ambient temperature, as noted by Tom's Hardware, demonstrates its robust thermal management capabilities. Additionally, the HX850's design allows for optimal airflow through the case, contributing to overall system cooling performance. The unit's heat dissipation was particularly effective under sustained loads, with no signs of thermal throttling or performance degradation.
Real-World Testing Results
Real-world testing by PC Perspective provided comprehensive data on the HX850's performance under various conditions. The testing methodology involved precise DC load testing using specialized equipment including programmable DC loads, precision resistor banks, and digital multimeters. The results showed that the HX850 maintained excellent voltage regulation across all outputs, with the +12V rails staying within ±2% of recommended guidelines even under full load. The power supply's ability to maintain stable voltage under different load conditions is crucial for system stability and performance, especially in high-end gaming and overclocking setups. The testing also revealed that the HX850's AC ripple and noise levels were well-controlled, with the +12V output staying exceptionally low even at full load, which is critical for preventing interference with sensitive components.
Legit Reviews conducted extensive testing that confirmed the HX850's reliability and performance characteristics. The testing included efficiency measurements, noise levels, and thermal performance under various load conditions. The unit's ability to maintain consistent performance across different load scenarios was particularly impressive, with no significant drops in efficiency or increases in noise levels. The power supply's 80 PLUS Platinum certification was validated through rigorous testing, showing that it delivers up to 90% energy efficiency under real-world conditions. The testing also confirmed that the HX850's 10-year warranty and lifetime access to technical support provide excellent long-term value for users.
Where It Falls Short
Despite its many strengths, the Corsair HX850 does have some drawbacks that potential buyers should consider. One significant limitation is the OCP (Over Current Protection) at 5VSB, which was noted by Tom's Hardware as a potential concern. This issue could affect the power supply's ability to handle certain types of loads, particularly in systems with high demands on the 5VSB rail. Additionally, the unit's bulky design, as mentioned by KitGuru, can be a challenge in smaller cases where space is limited. The power supply's size of 150mm x 86mm x 180mm means it may not fit in all compact builds, limiting its versatility in certain configurations.
Another limitation is the relatively high conducted EMI compared to other units in its class, according to Tom's Hardware. This could be problematic for users who require extremely low electromagnetic interference, particularly in sensitive audio or video setups. The HX850 also includes bulky ATX, EPS, and PCIe cables, which some users might find less convenient than more compact alternatives. Furthermore, while the unit's modular design is generally praised, the cable management can be challenging in some cases, particularly when dealing with multiple cables and limited space in the case. The unit's price point, while competitive, may be higher than some users are willing to pay, especially when compared to similar units from competitors like Seasonic or EVGA.
Who It's Best For
The Corsair HX850 Platinum is best suited for enthusiasts and professionals who demand high performance, reliability, and quiet operation in their systems. It's particularly well-suited for high-end gaming builds, overclocking systems, and workstations where stable power delivery is crucial. According to PC Perspective's review, the HX850's single +12V rail design and excellent voltage regulation make it ideal for modern graphics cards and other high-power components. The unit's ability to operate silently under low loads makes it perfect for quiet gaming environments, while its robust performance under full load ensures it can handle demanding applications without issues.
The HX850 is also an excellent choice for users who value long-term reliability and support. With its 10-year warranty and lifetime access to Corsair's technical support, it offers excellent value for users who want a power supply that will last. However, users who prioritize ultra-low cost or require very specific features like extremely low EMI might find better alternatives in the market. Additionally, those with very compact builds may find the unit's size to be a limiting factor, as it's not designed for small form factor systems.
How It Compares to Alternatives
When compared to its direct competitors, the Corsair HX850 Platinum holds its own in terms of performance and features. Tom's Hardware noted that it competes directly with the EVGA 850 G3 and Seasonic FOCUS PLUS Gold and Platinum units, with the HX850 offering superior silent operation. The unit's 80 PLUS Platinum certification and excellent efficiency ratings put it ahead of many competitors in terms of energy efficiency. However, the HX850's price point is slightly higher than some alternatives, which may be a consideration for budget-conscious buyers. According to KitGuru, the HX850's modular design and build quality are superior to many competing units, though the unit's size and EMI levels are areas where it falls short compared to some rivals.
In comparison to other high-end power supplies, the Corsair HX850 stands out for its combination of efficiency, quiet operation, and reliability. While some competitors like the Seasonic Focus Plus series offer similar performance, the HX850's 10-year warranty and Corsair's reputation for quality support give it an edge in long-term value. The unit's ability to operate silently under low loads, combined with its robust performance under full load, makes it a strong contender in the mid-to-high-end market. However, users seeking the absolute lowest cost or those requiring very specific features like ultra-low EMI might find better alternatives in the market, particularly from competitors who specialize in niche requirements.
Value at This Price
The Corsair HX850 Platinum offers excellent value for money, particularly when considering its 10-year warranty and comprehensive feature set. The unit's 80 PLUS Platinum certification, combined with its exceptional efficiency and quiet operation, makes it a premium product that delivers on its promises. According to PC Perspective, the HX850's performance justifies its price point, especially for users who require high-quality power delivery and long-term reliability. The unit's ability to maintain stable performance under various load conditions, along with its excellent voltage regulation and low noise levels, provides significant value for enthusiasts and professionals.
The unit's performance in real-world testing, as demonstrated by multiple reviewers, validates its premium positioning. The power supply's ability to handle demanding applications while maintaining quiet operation and excellent efficiency makes it a solid choice for users who prioritize quality and reliability over cost savings. However, budget-conscious buyers might find better value in competing units that offer similar performance at a lower price point, particularly if they don't require the extended warranty or advanced features.
Strengths
- +Full power at 46°C ambient temperature
- +90% efficiency at real-world load conditions
- +ZeroRPM mode for fanless operation at low loads
- +Fully modular design with clean installation
- +10-year warranty
Watch-outs
- −OCP at 5VSB
- −Bulky ATX, EPS and PCIe cables
Who this is for
Why you’d buy the Corsair HX850
- Full power at 46°C ambient temperature.
- 90% efficiency at real-world load conditions.
- ZeroRPM mode for fanless operation at low loads.
Why you’d skip it
- OCP at 5VSB.
- Bulky ATX, EPS and PCIe cables.
Rating sources
“Corsair gives the HX850 PSU an overhaul and sets a new benchmark for DC output quality in the process.”
“The Corsair HX850 Platinum power supply was evaluated on both features and performance. A full range of equipment was used to test the power supply under controlled load conditions.”
Our 4.6 score is the average of these published ratings. Ratings marked * were derived from the reviewer’s written analysis or video transcript — the publisher didn’t print an explicit numeric score, so we inferred one from their own words. Click through to verify. More about methodology.
