ASUS Prime B850M-K AMD AM5 Micro-ATX Motherboard

The ASUS Prime B850M-K is a Micro-ATX motherboard designed for AMD’s AM5 platform, supporting Ryzen 9000, Ryzen 8000, and Ryzen 7000 Series desktop processors. Built around the AMD B850 chipset, it combines modern PCIe 5.0 connectivity, high-speed DDR5 memory support, fast storage, and 2.5Gb Ethernet in a compact motherboard design.

The motherboard features two DDR5 DIMM slots supporting up to 128GB of memory in dual-channel configuration. It supports AMD EXPO and ASUS AEMP for memory optimization, with speeds reaching up to 8200+MT/s (O.C.) with Ryzen 9000 Series processors.

For graphics and expansion, the PRIME B850M-K provides a primary PCIe 5.0 x16 slot supporting x16 mode with Ryzen 9000 and 7000 Series processors. It also includes a secondary PCIe 4.0 x16 slot operating at x4 through the B850 chipset.

Storage connectivity includes two M.2 slots. The primary M.2 slot supports PCIe 5.0 x4 and 2280 drives, while the second slot supports 2242, 2260, and 2280 drives using PCIe 4.0 x4. The motherboard also provides four SATA 6Gb/s ports.

Networking is handled by a Realtek 2.5Gb Ethernet controller, providing faster wired network performance than standard Gigabit Ethernet. The rear I/O also includes USB 10Gbps Type-A ports, USB 5Gbps Type-A ports, USB 2.0 ports, HDMI 2.1, DisplayPort 1.4, and a PS/2 keyboard/mouse combo port.

The PRIME B850M-K uses an 8+2+1 phase digital power design with Digi+ VRM control and a six-layer PCB. ASUS also includes VRM and M.2 heatsinks, Fan Xpert 2+, Q-Design features, BIOS FlashBack, and Aura Sync support for system customization and easier PC building.

Key Features

• AMD B850 chipset
• AMD AM5 socket
• Supports Ryzen 9000, 8000, and 7000 Series desktop processors
• Supports CPUs up to 170W
• 2 × DDR5 DIMM slots
• Up to 128GB memory capacity
• Dual-channel memory architecture
• DDR5 up to 8200+MT/s (O.C.) with Ryzen 9000
• AMD EXPO and ASUS AEMP support
• 1 × PCIe 5.0 x16 slot
• 1 × PCIe 4.0 x16 slot operating at x4
• 2 × M.2 NVMe slots
• PCIe 5.0 x4 + PCIe 4.0 x4 M.2 support
• 4 × SATA 6Gb/s ports
• Realtek 2.5Gb Ethernet
• HDMI 2.1 and DisplayPort 1.4
• USB 10Gbps Type-A support
• Front USB 5Gbps Type-C support
• BIOS FlashBack
• ASUS Aura Sync
• ASUS Fan Xpert 2+
• 8+2+1 phase digital power design
• Micro-ATX form factor

Technical Specifications