This article covers 【限定】ASUS Intel CPU Core Ultra Processors (Series 2) LGA1851 対応 B860 Chipset mATX マザーボード.

Overview

The ASUS PRIME B860M-K-CSM is a microATX motherboard built for Intel Core Ultra processors (Series 2) on the LGA1851 socket. Featuring the B860 chipset, it supports DDR5 memory and a PCIe 5.0 slot while keeping costs down, positioning it as an entry-level option for budget-conscious builders. This motherboard is ideal for users who want to build a cost-effective desktop PC with a Core Ultra 5 or Core Ultra 7. It supports up to 256GB of DDR5 memory (overclocked to 8666+ MT/s) and includes a PCIe 5.0 x16 slot for modern graphics cards. The M.2 slots are PCIe 4.0 x4, and there are four SATA 6Gb/s ports. However, this -exclusive model has reduced USB connectivity: it lacks the USB 20Gbps Type-C and USB 10Gbps Type-C ports. Standard USB 5Gbps ports are available, but if you need high-speed USB-C, consider a different model.

Compatibility Guide

The CPU socket is LGA1851, compatible only with Intel Core Ultra processors (Series 2). Older LGA1700 or LGA1200 CPUs are not supported. Memory support is DDR5 only, with four DIMM slots for up to 256GB. Overclocking support reaches 8666+ MT/s, and XMP 3.0/EXPO profiles are enabled for easy tuning. Expansion includes one PCIe 5.0 x16 slot and one PCIe 3.0 x16 slot (x4 electrical). Storage: two M.2 slots (PCIe 4.0 x4) and four SATA 6Gb/s ports. The M.2 slots are connected via the chipset and CPU respectively. Form factor is microATX (24.4cm x 24.4cm), fitting most mATX cases. Power connectors: 24-pin ATX and one 8-pin EPS. A standard ATX power supply rated 650W or higher is recommended for a typical build with a mid-range GPU.

Product Info

The ASUS PRIME B860M-K-CSM launched around January 2025 as part of the entry-level to mid-range market segment. Priced at approximately ¥22,000 (as of July 2026 at Japan), it offers a 3-year manufacturer warranty. It includes Realtek 2.5GbE LAN, HDMI 2.1 and DisplayPort 1.4 outputs, and RGB headers. Note that Wi-Fi is not included—you'll need a separate adapter.

Best Use Cases

Budget Gaming Build: Pair with a Core Ultra 5 and a GeForce RTX 4060/AMD Radeon RX 7600 for solid 1080p gaming. The board's limited USB ports are less of an issue, and the PCIe 5.0 slot ensures GPU bandwidth is not a bottleneck. Office/Productivity: For general office work, programming, or light video editing, this board provides a stable platform with fast DDR5 and M.2 SSD support at a low cost. Compact SFF Build: The microATX form factor allows for small cases. However, limited PCIe slots mean you can't add many expansion cards—best for single-GPU setups. Intel Core Ultra First-Timer: If you want to try the latest LGA1851 platform without spending heavily, this board is a great entry point. Pair with a Core Ultra 5 225H or similar.

Things to Consider

The -exclusive version cuts USB 20Gbps and USB 10Gbps Type-C ports. If you need fast USB-C for external SSDs or VR headsets, this board is not suitable. Consider the PRIME B860-PLUS for full USB connectivity. There is no PCIe 5.0 M.2 slot; both M.2 slots are PCIe 4.0 x4. For the fastest Gen5 SSDs, you'll need a higher-tier motherboard. Also, the B860 chipset does not allow CPU multiplier overclocking—only memory overclocking is supported. Wi-Fi is not included; you must add a PCIe or USB Wi-Fi adapter for wireless connectivity. The VRM design is modest, so avoid pairing with Core Ultra 9 processors under sustained heavy loads to prevent thermal throttling. ## FAQ
Q: Can I use a Core Ultra 9 285K with this motherboard? A: Yes, it is socket-compatible, but the VRM is not designed for high-end CPUs under full load. For Core Ultra 9, we recommend a motherboard with a stronger VRM, like the PRIME B860-PLUS or ROG STRIX B860-F. Q: Does it support DDR5-8000 memory? A: Officially supports up to 8666+ MT/s (OC). DDR5-8000 is within that range, but stability depends on the memory kit and BIOS version. Update to the latest BIOS for best compatibility. Q: Are there any PCIe 5.0 M.2 slots? A: No. Both M.2 slots are PCIe 4.0 x4. If you need PCIe 5.0 M.2, look at the PRIME B860-PLUS or other higher-end B860 boards.

Product Disclosure (Amazon)

  • Manufacturer: ASUS
  • Seller: Amazon.co.jp
  • Fulfilled by: Amazon.co.jp
  • ASIN: B0F5GD2VRW
  • Note: This article covers a manufacturer-made product based on Amazon listing details.