MSI MAG A850GL 850W Power Supply: features, specs and who it suits

The MSI MAG A850GL is an 850-watt ATX power supply aimed at gaming PCs. It's fully modular, 80 PLUS Gold certified and built to the ATX 3.0 and PCIe 5 standards used by recent graphics cards. Here is what each of those terms means and what to check before fitting one.

What 850 watts covers

The wattage of a power supply is the most it can deliver, not what the PC draws all the time. A typical gaming PC uses far less than its power supply's capacity most of the time and approaches it only under heavy load. An 850W unit generally leaves comfortable headroom for a mid- to high-end graphics card and a modern processor, but you should add up your own components' rated power to be sure, and leave a margin.

ATX 3.0 and PCIe 5

MSI lists the unit as ATX 3.0 and PCIe 5. In general, ATX 3.0 is the Intel power-supply design update written around modern graphics cards, which can briefly spike well above their average power. It also covers the newer 12-volt high-power connector found on recent cards. PCIe 5 refers to the platform generation those cards belong to. Check the manual and your graphics card's documentation for the exact cable and connector you need.

80 PLUS Gold efficiency

80 PLUS is a certification programme that tests how efficiently a power supply converts mains power into the lower voltages a PC uses. Gold is a mid-to-upper tier, typically requiring roughly 87 to 90 percent efficiency at common loads. A more efficient unit wastes less energy as heat, so less cooling is needed.

Fully modular design

With a fully modular power supply, every cable detaches. You connect only the leads you need, so there are fewer cables in the case, which makes building and tidying easier and can help airflow. As a rule, only use the cables supplied with the specific unit, as the pin layouts differ between brands and models.

Compact size and fit

MSI calls the A850GL compact. The listing gives dimensions of 12.0 x 8.7 x 4.9 inches and a weight of 6.2 lb (about 2.8 kg), which appear to include packaging, so check the unit's own length in the manual or on MSI's specifications. A shorter power supply gives more room for cables in smaller cases, which matters in compact builds.

Warranty

MSI lists a ten-year limited warranty. The terms and conditions of the warranty matter as much as its length, so read them for what is and isn't covered.

Who it suits

It suits people building or upgrading a gaming or general-purpose desktop with a current-generation graphics card who want a modular unit with modern connector support. If your system draws a lot less, a lower-wattage unit may be enough. If you plan on a very power-hungry graphics card, check that 850W is sufficient.

What to check before you buy

• Power needs: add up your processor and graphics card's rated power and leave headroom.
• Graphics card connector: confirm the cable type your card needs and that it's supplied.
• Case fit: check the maximum power-supply length your case allows.
• Cable count: make sure there are enough SATA, drive and CPU connectors for your build.
• Warranty terms: read what the ten-year limited warranty covers.
• Safe fitting: follow the manual, and switch off and unplug the PC before changing cables.

The short version

• An 850W fully modular ATX power supply from MSI.
• ATX 3.0 and PCIe 5 support for recent graphics cards.
• 80 PLUS Gold certified.
• Described by MSI as compact, with a ten-year limited warranty.
• Check your total power need and case fit before buying.

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