MSI’s Test of MPG A850G PCIE 5.0: Performance Evaluation and Insights

Aimed at gamers, the MPG A850G PCIE 5.0 is a powerful power supply designed to meet the power needs of the latest generation graphics cards. It supports the ATX 3.0 standard and meets the requirements of the 80 Plus Gold label.

Its mechanics offer high efficiency that minimizes losses in the form of heat. It comes with a 12VHPWR harness with a little trick to avoid bad connections, while the wiring management is 100% modular. Added to all this is semi-fanless cooling and 850W of power under the hood.

Alimentation MPG A850G PCIE 5.0

We tested it using the duo of a Core i9-10900K and a GeForce RTX 4090. Is it silent? Are tensions stable?

MPG A850G PCIE 5.0 overview

The MPG A850G PCIE 5.0 is part of a range that offers different power options. Its design and features are primarily targeted at gamers seeking connectors that fulfill the requirements of the high-end GeForce RTX 40 series.

Its bundle is relatively standard, comprising the unit itself, mounting screws, and modular cables in a pouch. This setup is practical because the fully modular cabling management enables users to connect only the essential components, allowing for easy storage of unused cables. It’s worth noting that this selective cabling approach simplifies assembly, facilitates storage within a case, and optimizes airflow.

Most of the cables are designed in a standard manner, except for the 2 x PCIe 6+2 pin harness, the 12VHPWR, and the ATX cables, which feature a round and sheathed design.

With 850 Watts under the hood, the block offers:

  • 1 x ATX 24 pin,
  • 2 x EPS 4+4 pins,
  • 1 x 12VHPWR,
  • 8 x SATA,
  • 4 x Molex,
  • 6 x PCIe 6+2 pin,
  • 1 x floppy

With dimensions of 150 x 150 x 86 mm, the block is relatively compact, which guarantees compatibility with all ATX cases.

Alimentation MPG A850G PCIE 5.0

MSI opts for a black steel dress with deep-drawn parallel lines on the side accompanied by the brand’s logo with a matte black finish and the MSI name with an aluminum finish. The whole brings a racy style.

Alimentation MPG A850G PCIE 5.0

The approach remains consistent on the fan grille side. It’s integrated into the chassis and consists of several parallel bars designed to facilitate airflow. However, it’s worth noting that this design isn’t the most optimal for achieving silence.

Cooling is managed by a 135 mm hydrodynamic bearing fan. Its operation includes a fanless mode, wherein if the load is less than 40%, the fan remains inactive. This mode can be activated using a small button located on the back, next to the power plug of the power button.

A sticker on the unit displays its primary electrical certifications and specifications. Notably, it reveals a single-rail power supply utilizing the LLC Half Bridge topology with a modular DC-DC design capable of delivering 70.81A on the +12V line, and 22A each on the +5V and +3.3V lines.

MPG A8500G
AC Input100 V-240 V~, 10 A, 50~60 Hz
DC Output+5 V+3.3 V+12 V-12 V+5 Vsb
22,0 A22,0 A70,8 A0,3 A3,0 A
Total Power120 watts850 watts3,6 watts15 watts
850 watts

The 80 Plus Gold certification provides assurance of high efficiency, thereby limiting energy waste in the form of heat and reducing cooling requirements.

Moreover, its compatibility with Intel PSDG (Power Supply Design Guide) ATX 3.0 standards ensures its capability to handle a total power demand twice as high as its rated power and a peak GPU power three times higher.

The inclusion of a 600-watt 12VHPWR rail ensures native support for the GeForce RTX 40 series. To aid in correct connections, MSI has adopted a yellow color scheme for these two connection plugs, serving as a visual aid for users.

Alimentation MPG A850G PCIE 5.0

Si vous voyez cette couleur une fois le câblage monté c’est que les branchements ne sont pas bons !

Finally, the block comes with several security features including OCP, OTP, OVP, OPP, UVP, and SCP protections. It has a 10-year warranty.

Test protocol.

Test Setup

  • Motherboard: Asus ROG Maximus XII Extreme
  • Processor: Core i9-10900K,
  • RAM : 4 x 8 Go de DDR4-3200 Dominator Platinum RGB (Pas d’XMP)
  • Graphics: Gigabyte GeForce RTX 4090 Gaming OC,
  • Heatsink: Noctua NH-D15 Chromax.Black,
  • Storage: Corsair MP400 2TB,

We found several pieces of data:

  • Fluctuations of +12V and +5 Volts using two digital voltmeters at several locations,
  • The values of the PFC,
  • Noise pollution,
  • The overall power consumption of the test configuration.

PFC and power consumption are measured using a digital power meter during several exercises: first at rest with the operating system loaded, but without any activity, then during a CPU and GPU test at 100% of its load. Each test is repeated three times and the average is calculated. We use the OCCT 12.0.5 (Test Power) utility.

CAUTION. The maximum fuel consumption is recorded without the Thermal Throttling technology being activated. The needs of our Core i9-10900K are between 285 and 290 Watts while those of the graphics card (RTX 4090) are between 445 and 450 Watts.

You will also find an evaluation of the financial and environmental cost over a year of our test platform (processor, motherboard, graphics card, etc.).

MPG A850G PCIE 5.0, performance.

Voltage fluctuation.

Alimentation MPG A850G PCIE 5.0 - Stabilité des tensions
MPG A850G PCIE 5.0 Power Supply – Voltage Stability

Our configuration can push the energy demand to the limits of the power supply’s possibilities. Despite this extreme situation, he manages to deliver stable tensions. We recorded a variation of about 0.7% on the +5V line compared to 0.2% on the +12V line. It’s perfect far from the maximums allowed by the ATX standard. We find the profile of the GX III 850 Gold from Cooler Master.

PFC values.

This value is framed by the 80 Plus certification. Its objective is to ensure that the electricity network is cleaned up by limiting the return of harmonics. The closer the power supply is to 1, the more it is considered a “clean” block.

Alimentation MPG A850G PCIE 5.0 - Valeur du PFC
MPG A850G PCIE 5.0 Power Supply – PFC Value

The PFC is between 0.77 and 0.98 depending on the charge level. The GX III 850 Gold does a little better, especially at rest, while the Focus GX-850 is just behind, but with a minimal difference only at rest (0.66 vs. 0.67).

MPG A850G PCIE 5.0, environmental assessment


Alimentation MPG A850G PCIE 5.0 - Nuisances sonores
MPG A850G PCIE 5.0 Power Supply – Noise Pollution

With the hybrid mode active and at rest, the fan does not spin. The MPG A850G PCIE 5.0 is inaudible. We only have room noise since the graphics card is also in fanless mode and the cooler is idling. There is no noise. At a high load (830W), the fan starts up and stabilizes at a fairly low speed, which limits noise pollution. Our sound level meter does not exceed 34.8 dBA.

On the other hand, from time to time and quickly, the fan rises in the revs. For a few seconds, the hiss is more present (41.6 dBa).

Power consumption

As we have seen, the presence of the 80 Plus Gold label guarantees a high efficiency limiting energy losses in the form of heat. The overall consumption of the platform is thus closer to the actual demand for our configuration.

Alimentation MPG A850G PCIE 5.0 - Consommations électriques
MPG A850G PCIE 5.0 Power Consumption – Power Consumption

Depending on the charge level, we record a consumption between 66.6 and 844.3 Watts. We are a little above its big sister of 1000 Watts labeled 80 Plus Platinum.


In operation, the MPG A850G PCIE 5.0 delivers reliable performance thanks to its robust and responsive mechanism. It maintains stable voltages and operates quietly. While it can meet the demands of a high-performance configuration, it’s worth noting that we are operating at its power limit in our case.

The ATX 3.0 and PCIE 5 certifications are valuable assets for modern setups, and the 12HPWR harness with color-coded plugs provides a simple yet highly effective solution to ensure correct connections. The included pouch for storing unused cables and the 100% modular wiring management further simplify installation and optimize storage within a case.

Overall, the balance is positive, especially considering its modest size and an appealing price point of around €140.

Mohamed SAKHRI
Mohamed SAKHRI

I'm the creator and editor-in-chief of Tech To Geek. Through this little blog, I share with you my passion for technology. I specialize in various operating systems such as Windows, Linux, macOS, and Android, focusing on providing practical and valuable guides.

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