Corsair
Corsair RMX Series, RM850x, 850 Watt, 80+ Gold Certified, Fully Modular Power Supply (Low Noise, Zero RPM Fan Mode, 105°C Capacitors, Fully Modular Cables, Compact Size) Black
As an Amazon Associate, SpecPicks earns from qualifying purchases.
*Price sourced from Amazon.com. Last updated 2026-08-17. Price and availability subject to change.
Bottom line: The Corsair RMX Series, RM850x, 850 Watt, 80+ Gold Certified, Fully Modular Power Supply (Low Noise, Zero RPM Fan Mode, 105°C Capacitors, Fully Modular Cables, Compact Size) Black is a specs-and-price decision rather than a crowd-consensus one in the power supplies category, priced around $139.99. Check the specification table above against one or two close alternatives — on price and spec fit, not on star ratings.
Corsair's RM850x delivers 850 watts of 80 PLUS Gold-certified power to your PC, and the spec sheet explains why it holds a 4.8 out of 5 rating across 13,071 reviews. Every capacitor inside is a 100 percent industrial-grade, 105 degree C Japanese unit, and the whole supply is backed by a ten-year warranty — the kind of coverage that outlasts two or three GPU upgrades. Zero RPM Fan Mode keeps the 5.3-inch fan completely stopped at low and medium loads, so your build stays silent until you actually push it; at maximum draw the low-noise fan takes over without turning your case into a wind…
SpecPicks Verdict
SpecPicks scored Corsair RMX Series, RM850x, 850 Watt, 80+ Gold Certified, Fully… using a rating × review-volume × price-fit model applied to our editorial and benchmark analysis across the power supplies category. Corsair's power supplies lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.
Common buyer scenarios for power supplies of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the Amazon listing before purchase. Prices, stock, and Prime eligibility update directly from Amazon's catalog and may have moved since this page was last verified.
Frequently Asked Questions
Is 850W enough for an RTX 4090 or 5090 build?
The RM850x delivers a continuous 850W rated at 50C ambient, which covers a single high-end GPU paired with a mainstream CPU. Check your specific GPU maker's recommended PSU wattage before buying, since transient spikes vary by card.
How long is the Corsair RM850x warranty?
Corsair backs the RM850x with a ten-year warranty. Confirm current registration and coverage terms on the product listing, as warranty policies can vary by region.
Does the fan run all the time?
No. Zero RPM Fan Mode keeps the fan fully stopped at low and medium loads, so the unit is silent during desktop work and light gaming. The 5.3-inch low-noise fan only spins up as load climbs.
Is the RM850x fully modular or semi-modular?
Fully modular. Every cable detaches, including the 24-pin, so you install only the connectors your build actually uses — helpful for airflow in a compact case.
Does the RM850x work with Corsair iCUE software?
No. Corsair lists iCUE Compatibility as No for this unit, and it is also not Modern Standby compatible. You get 80 PLUS Gold efficiency and Zero RPM operation without any software layer.
Pros & Cons
Pros
- ✓ 80 Plus Gold certified for lower power consumption, less noise and cooler temperatures
- ✓ Backed by Corsair's warranty and support channels
- ✓ Ships via Amazon with Prime eligibility and the standard returns policy
Cons
- ✗ Confirm socket / form-factor / power-rating compatibility against your build before ordering
- ✗ Price, stock, and Prime eligibility update from Amazon and may have changed since this page was last verified
Key Features
- 80 Plus Gold certified for lower power consumption, less noise and cooler temperatures
- For maximum cooling surface area and performance
- Zero RPM fan mode for near silent operation at low to medium loads; Continuous output rated temperature: 50°C
- 100 percent industrial grade, 105°C rated Japanese capacitors ensure unwavering power and reliability
- Fully modular cables, so you only connect the cables your system needs. Fan size-5.3 inches iCUE Compatibility-No. Modern Standby Compatible- No
Full Specifications
| Brand | Corsair |
|---|---|
| Wattage | 850 watts |
| Fan Size | 13.5 centimeters |
| Model Name | RMx |
| Form Factor | ATX12V |
| Model Number | CP-9020180-NA |
| Connector Type | ATX, EPS |
| Cooling Method | Air |
| Item Type Name | Computer Power Supply |
| Number of Fans | 1 |
| Output Wattage | 850 |
| Item Dimensions | 6.3 x 5.91 x 3.39 inches |
| Mfr Part Number | CP-9020180-NA |
| Compatible Devices | Personal Computer |
| Connector Quantity | 36 |
| Power Supply Design | Full Modular |
| Warranty Description | 10 years warranty |
| Maximum Input Voltage | 120 volts_of_alternating_current |
| Minimum Input Voltage | 100 volts_of_alternating_current |
| Item dimensions L x W x H | 6.3 x 5.91 x 3.39 inches |
Ready to buy?
Corsair RMX Series, RM850x, 850 Watt, 80+ Gold Certified, Fully Modular Power Supply (Low Noise, Zero RPM Fan Mode, 105°C Capacitors, Fully Modular Cables, Compact Size) Black is available on Amazon with Prime shipping and the full Amazon returns policy. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.
View Current Price on Amazon →
*Price sourced from Amazon.com. Last updated 2026-08-17. Price and availability subject to change.
Related Power Supplies
More guides & deep dives from the SpecPicks archive
Browse all articles & guides →- How to Build a Windows 98 Retro PC in 2026
- Best Retro Handhelds in 2026 — From $35 to $500
- Emulation Hardware in 2026: FPGA, Software, and Cart-Reader Ecosystems
- RTX 4070 Super vs RX 7800 XT — Which to Buy in 2026
- Best 1440p Gaming GPUs in 2026
- Best Budget Gaming PC Build 2026 — ~$1,000 ($800 on Sale)
- The Complete Voodoo5 5500 AGP Driver Guide (2026 Edition)
More reviews from the SpecPicks archive
Browse all reviews →- Best Retro PC Upgrade Kit 2026: Sound & Storage
- GPU & CPU Upgrade ROI: Cost-per-FPS Calculator Guide
- AMD Ryzen AI Halo: Pre-Orders Open for Linux Developers
- Best PlayStation 5 Controllers in 2026: 5 Picks for Every Player
- Intel Arc B580 & Arc Pro B60 24GB vs RTX 3060 12GB for Local LLMs
- Best Budget CPU for Gaming + Productivity in 2026: The Honest Buying Guide
- Building a Period-Correct Windows 98 Gaming PC in 2026: Parts, Pitfalls, and Driver Archaeology
- Second Streaming PC vs NVENC: What an Old i7-9700K Is Still Good For
- Is the Ryzen 7 5800X Still Worth It for 1440p Gaming in 2026?
- vLLM Framework Vulnerability: What Local LLM Operators Need to Patch in 2026
- Building a Silent Pentium III Windows 98 Gaming Rig in 2026
- Best GPU for Qwen3 30B-A3B: What the 3B Active Path Really Needs
- Hailo-10H AI Accelerator on Raspberry Pi 5: Real Tok/s for On-Device LLMs
- ESP32-S3 vs RP2350 vs Nordic nRF54L15: Which MCU for On-Device AI in 2026?
- Adding USB Storage to a Windows 98 PC With a SATA/IDE Adapter
- Voodoo3 3000 PCI No-Display Troubleshooting on Windows 98 SE (2026)
- Best SSD for a Local AI / LLM Workstation in 2026
- AI Coding Agents Find the Right File but Miss the Lines — What Local Code Models on a 12GB GPU Get Wrong
- NVIDIA Nemotron 3 Ultra: What It Takes to Run Locally
- Best Controller for Fighting Games on PC in 2026: HORI HORIPAD vs 8BitDo Pro 2 vs DualSense
- OpenAI and Anthropic Are Giving Startups Free Compute — Here's the Local Rig That Replaces It
- Best GPU for 1080p Esports in 2026: Why the RTX 3060 12GB Still Delivers
- Best Controller for Retro Emulation on PC: 8BitDo Pro 2 vs GameSir G7 SE
- Best Storage for a Retro PC Build in 2026
Earliest SpecPicks reviews
Browse full archive →- Best GPU for Llama 3.1 8B (2026)
- Best GPU for Qwen 3 14B (2026)
- Best GPU for Qwen 3 32B (2026)
- Best GPU for Llama 3.1 70B (2026)
- Best GPU for DeepSeek-R1 32B (2026)
- Best GPU for Llama 3.1 405B (2026)
- How to run Llama 3.1 8B on NVIDIA GeForce RTX 5090
- How to run Qwen 3 14B on NVIDIA GeForce RTX 5090
- How to run Qwen 3 32B on NVIDIA GeForce RTX 5090
- How to run Llama 3.1 70B on NVIDIA GeForce RTX 5090
- How to run DeepSeek-R1 32B on NVIDIA GeForce RTX 5090
- How to run Llama 3.1 8B on NVIDIA GeForce RTX 4090