ASRock B860 Steel Legend WiFi ATXマザーボード MB6699

This article covers ASRock B860 Steel Legend WiFi ATXマザーボード MB6699.

Overview

The ASRock B860 Steel Legend WiFi is an ATX motherboard built around Intel's B860 chipset, supporting the latest Core Ultra processors (Series 2) via the LGA1851 socket. It brings DDR5 memory support, a PCIe 5.0 M.2 slot, and a robust VRM design with 80A Dr.MOS. Priced around ¥27,800 in Japan, it sits in the mid-range segment but offers premium connectivity including Thunderbolt 4, Wi-Fi 6E, and 2.5GbE LAN. ASRock's signature 20K long-life capacitors and a large heatsink armor keep temperatures in check, while tool-less M.2 heatsinks simplify installation. This board is a solid choice for builders who want a feature-rich platform without stepping up to the more expensive Z-series chipsets.

Compatibility Guide

CPU socket LGA1851 is exclusive to Intel Core Ultra (Series 2) processors — earlier generations like Raptor Lake or Alder Lake are not compatible. Four DDR5 DIMM slots support up to 256GB, with XMP 3.0 profiles reaching speeds beyond DDR5-8666 (depending on CPU memory controller). The motherboard follows the standard ATX form factor (305×244mm), fitting most mid-tower and full-tower cases. Expansion includes one PCIe 5.0 x16 slot and one PCIe 4.0 x16 slot (electrical x4). For storage, there are four M.2 slots: one PCIe 5.0 x4, two PCIe 4.0 x4, and one PCIe 4.0 x2, plus four SATA3 ports. The primary M.2 slot benefits from a dedicated heatsink.

Product Info

Launched in early 2025, the B860 Steel Legend WiFi targets the mid-range market with a price typically falling between ¥25,000 and ¥30,000. The board comes with a standard 3-year warranty from ASRock. It is widely available through major retailers and online platforms like . From a market-position standpoint, this motherboard stands out by combining a B860 chipset — which usually lacks Thunderbolt — with a Thunderbolt 4 Type-C port. This makes it a unique value proposition compared to similarly priced competitors from ASUS and MSI.

Best Use Cases

Gamers building a Core Ultra 5 or Ultra 7 system will find this board an excellent fit. Pair it with a single high-end GPU (e.g., RTX 5070) for smooth 1440p high-refresh-rate gaming. The PCIe 5.0 M.2 slot ensures fast game loading, and the 2.5GbE LAN keeps online multiplayer latency low. Content creators who work with large video files or 3D assets will appreciate the Thunderbolt 4 port for fast external storage or multi-monitor setups. The board's solid VRM design also handles sustained creative workloads without throttling. Finally, users looking for a reliable platform for a home server or workstation can benefit from the long-life capacitors and ample connectivity. The combination of Wi-Fi 6E and 2.5GbE offers flexible networking, and the four SATA ports support bulk storage arrays. ## Alternatives
Direct competitors in the same price bracket include the ASUS TUF GAMING B860-PLUS WIFI and the MSI MAG B860 TOMAHAWK WIFI. The ASUS board emphasizes military-grade durability and has a refined BIOS, but lacks Thunderbolt 4. The MSI model boasts a beefier VRM heatsink and more extensive overclocking features in the BIOS, but also omits Thunderbolt. Where the ASRock Steel Legend WiFi shines is its Thunderbolt 4 Type-C port — a rare inclusion on B860 boards. If you need Thunderbolt for external GPUs, high-speed storage, or docking stations, this is the motherboard to choose. However, if you prioritize BIOS polish or extreme memory overclocking, you might prefer the ASUS or MSI alternatives.

Things to Consider

The LGA1851 socket currently only supports Intel Core Ultra (Series 2) CPUs, limiting your processor choices. For those planning to upgrade to future Arrow Lake-S chips, compatibility is not guaranteed — check ASRock's CPU support list regularly. Additionally, the B860 chipset does not allow CPU core overclocking, even with K-series processors. Memory overclocking is supported, but achieving DDR5-8000+ speeds heavily depends on the CPU's integrated memory controller quality. The second PCIe x16 slot runs at PCIe 4.0 x4 electrically, so its bandwidth is limited for dual GPU setups. Also, the chipset heatsink is relatively large; double-check CPU cooler clearance before installation to avoid interference.

Product Disclosure (Amazon)

• Manufacturer: ASRock
• Seller: MONOROCU(モノロク)【年中無休で迅速・丁寧に発送】
• Fulfilled by: Amazon
• ASIN: B0DRTVYZ17
• Note: This article covers a manufacturer-made product based on Amazon listing details.