bloiq.

Guides to buying well and travelling well

Home / Tech · Product overviews / Computers & Accessories / Motherboards · More from ASUS

ASUS Prime B840-PLUS WiFi Motherboard: AM5, DDR5 and PCIe 4.0 explained

An ATX AM5 motherboard with DDR5, PCIe 4.0, three M.2 slots, Wi-Fi 6E and 2.5Gb Ethernet. What the B840 chipset and connectivity mean for a PC build.

By Bloiq Editors · October 27, 2026 · 3 min read

This page contains an affiliate link, marked as such. If you buy through it, Bloiq may earn a commission at no extra cost to you.

The ASUS Prime B840-PLUS WiFi is an ATX motherboard for AMD's AM5 socket. It uses the B840 chipset and offers DDR5 memory, PCIe 4.0, three M.2 slots and built-in wireless. Here is what those specs mean for a desktop build.

Socket and processor support

AM5 is AMD's current desktop socket. ASUS lists support for Ryzen 9000, 8000 and 7000 series desktop processors. Processor support can depend on the BIOS version on the board. BIOS FlashBack, listed in the description, lets you update the BIOS from a USB drive without a processor installed, which helps when a board needs a newer BIOS for a newer chip.

Memory

The board uses DDR5, the memory generation that AM5 requires. DDR5 modules are not interchangeable with DDR4. The listing does not state the number of slots or the maximum speed, so check ASUS's specification page for supported memory kits before choosing RAM.

PCIe 4.0 and storage

There is a PCIe 4.0 x16 slot for a graphics card and PCIe 4.0 M.2 slots for solid-state drives. PCIe 4.0 offers roughly double the bandwidth of PCIe 3.0, which suits current graphics cards and fast NVMe drives. ASUS lists three M.2 slots in total and heatsinks on the M.2 area to help control temperatures. Which slots run at PCIe 4.0 should be confirmed in the manual.

Connectivity

  • Wi-Fi 6E, which adds the 6GHz band to the usual two.
  • Realtek 2.5Gb Ethernet, faster than standard gigabit.
  • Rear USB 10Gbps Type-A and Type-C ports, and front USB 5Gbps Type-C support.
  • DisplayPort and HDMI outputs, for use with processors that have integrated graphics.

Power and cooling

ASUS lists a 6-layer PCB, alloy chokes and durable capacitors for stable power delivery. Cooling features include VRM, M.2 and PCH heatsinks, hybrid fan headers and the Fan Xpert 2+ tool. Aura Sync RGB lets you coordinate lighting with compatible components.

AI-ready claim

ASUS describes the board as ready for AI PCs, meaning the connectivity and power needed for demanding AI applications. The actual capability still depends on the processor and graphics card you pair with it.

Size

It is a full ATX board, about 12.0 x 9.6 inches (30.5 x 24.4 cm) and 2.3 lb (about 1 kg) as shipped. Check that your case supports ATX.

Who it suits

It suits people building or upgrading a mainstream AM5 desktop for gaming, work or home use who want PCIe 4.0 storage and built-in Wi-Fi.

What to check before you buy

  • Processor and BIOS: confirm your chip is supported and whether a BIOS update is needed.
  • Case size: the board is ATX.
  • Memory: make sure you buy DDR5 and check the supported kit list.
  • Graphics card: PCIe 4.0 x16 slot; check the card fits physically.
  • Ports: compare the list of rear and front ports with your devices.
  • Cooler: confirm it supports AM5 mounting.

The short version

  • ATX AMD AM5 motherboard with the B840 chipset.
  • DDR5 memory, PCIe 4.0 x16 and three M.2 slots.
  • Wi-Fi 6E, 2.5Gb Ethernet, USB 10Gbps Type-A and Type-C.
  • BIOS FlashBack, heatsinks and Aura Sync RGB.

Bloiq is reader-supported. Some links may earn us a commission; it never affects what we write. How we make money.

Keep reading