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Rectangular black metal PSU with mesh front and modular cable sockets visible

Rosewill Open box

Rosewill CMG850 850 W ATX 3.0/3.1 80+ Gold full modular power supply

SKU CH-RDGV-FBTX6 MPN CMG850

An 850 W ATX 3.0 and 3.1 compatible unit with 80 PLUS Gold efficiency, a single 12 V rail, full modular cables and a 120 mm FDB fan in a 140 mm chassis

  • Max wattage850 W
  • Power efficiencyUp to 92%
  • Modular cablingFull Modular
  • Fan configuration1 x Silent 120 mm FDB fan
  • Power factor correctionActive
  • Main power connector20+4Pin
  • 850 W single 12 V rail powers demanding builds
  • ATX 3.0 and 3.1 compatible for modern GPUs
  • Full modular cabling reduces clutter inside the case
  • 120 mm FDB fan runs quiet under load
  • 80 PLUS Gold certification delivers up to 92 % efficiency

850 W ATX 3.0/3.1 power supply

The Rosewill CMG850 delivers up to 850 W through a single +12 V rail. It carries 80 PLUS Gold certification with up to 92 % efficiency. The fully modular design lets builders connect only the cables their system needs. It targets desktop builders who want a compact, high-efficiency unit for modern graphics cards and multi-drive configurations.

ATX 3.0 and 3.1 compatibility

This unit meets both ATX 3.0 and ATX 3.1 specifications for transient response and power-excursion handling. A single strong 12 V rail simplifies load balancing across high-end GPUs. The 140 mm length fits many smaller cases where longer units would not. Hold-up time is rated at 16 ms minimum and power-good signal at 1-100 ms.

Four PCIe connectors and nine SATA ports

Four 6+2-pin PCIe connectors support multi-GPU SLI or CrossFire setups. Nine SATA power connectors provide ample drive capacity for storage-heavy builds. Two 4+4-pin EPS connectors feed modern motherboards. The 120 mm FDB fan runs silently while the 100-240 V active PFC input handles global mains without a switch.

How it compares

Measured against everything we stock in ATX Desktop Power Supplies, at today’s prices. Recalculated every night.

Price $58.99
Cheaper than about 86% of the 10,869 comparable items (median $142.99).
Max wattage 850 W
Typical for this category: the median of 930 items is 850 W.

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Specifications

Product
Brand nameRosewill
Model nameCMG850
Product typeATX 3.0 Compatible / ATX 3.1 Compatible
Graphics
SLI supportReady
CrossFire supportReady
Ports & slots
PCIe power connectors4 × 6+2-Pin
SATA power connectors9
Output type+3.3 V@18A, +5 V@18A
Connection types1 × 20+4-Pin Main Connector
2 × 4+4-Pin ATX12 V / EPS12 V Connector
4 × 6+2-Pin PCI-E Connector
9 x SATA Connector
4 × 4-Pin Peripheral Connector
Power
Max wattage850 W
Power efficiencyUp to 92%
Modular cablingFull Modular
Power factor correctionActive
Main power connector20+4Pin
12V railsSingle
Power good signal1-100 ms
Power hold-up time16 ms min.
Efficiency certification80 PLUS GOLD Certified
Supply voltage100–240 V
AC input frequency50/60 Hz
Size & build
Product dimensions3.39 in × 5.91 in × 5.51 in
Shipping weight2.84 kg
Package size290 × 226 × 117 mm
Compatibility
PSU length limit140 mm
Environment & compliance
Regulatory approvalscTUVus, FCC certified
More details
Fan configuration1 x Silent 120 mm FDB fan
Mean time between failures>100,000 h

Questions about this item

What does the 850 W rating mean once the unit is installed in a PC?

The single 12 V rail can deliver the full 850 W to graphics cards and CPU, so high-end gaming builds draw their peak power without rail balancing limits.

What does ATX 3.0 / 3.1 compatibility cap in practice?

The platform supports the 12 VHPWR power-excursion and timing requirements defined by ATX 3.0 and 3.1, allowing modern GPUs to trigger transient spikes within the spec window.

What clearance does the 140 mm length need in a case?

The chassis must provide at least 140 mm of depth from the PSU mounting face to any drive cage or cable routing barrier for the unit to fit.

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