Best Mini-ITX · Motherboards

ASUS ROG Strix B850-I Gaming WiFi

The ROG Strix B850-I packs two PCIe 5.0 M.2 slots, Wi-Fi 7 and strong power delivery into a tiny Mini-ITX board. It's the one to choose for a compact but powerful AM5 gaming PC.

Brand: ASUS
Best for: Small form factor AM5 builds
Price range: Upper mid-range
Our score: 8.5/10

Check today's price on Amazon.co.uk →

Our take

The ASUS ROG Strix B850-I Gaming WiFi packs high-end features into a tiny Mini-ITX board. With two PCIe 5.0 M.2 slots, Wi-Fi 7 and strong power delivery, it's our pick for a compact but powerful AM5 gaming PC.

Small but capable

Mini-ITX boards measure just 17 x 17cm, which lets you build a gaming PC in a case not much bigger than a shoebox. The trade-off is space: there's room for only two memory slots, one expansion slot and fewer connectors.

The Strix B850-I makes the most of it. Its 10+2+1 phase power delivery comfortably handles the Ryzen 7 9800X3D, the ideal processor for a small gaming PC thanks to its efficiency, and can run a Ryzen 9 too, though cooling a 16-core chip in a tiny case is the real challenge.

Storage and memory

Two M.2 slots, both PCIe 5.0, are rare on a Mini-ITX board. Fitting an M.2 drive under the stacked heatsink needs a screwdriver, which is a minor annoyance. Two DDR5 slots support up to 128GB and overclocked speeds up to around DDR5-8400. A 32GB or 64GB two-stick kit is ideal.

Connectivity

You get 2.5Gb Ethernet, Wi-Fi 7 and Bluetooth 5.4, a Clear CMOS button and BIOS Flashback. Reviewers noted the rear panel has fewer USB ports than larger boards, so a USB hub may help.

Platform

AMD has committed to supporting the AM5 socket until at least 2027, so the board can take a faster Ryzen processor later. Boards made before Ryzen 9000 launched may need a BIOS update first; this one supports BIOS Flashback, which updates the BIOS from a USB stick without a processor installed.

Who should buy it

Buy the ROG Strix B850-I for a compact, high-end AM5 gaming PC. If you have room for a larger case, an ATX board like the MSI MAG B850 Tomahawk MAX WiFi II gives you more features for less.

Key specifications

Socket	AMD AM5
Chipset	AMD B850
Form factor	Mini-ITX
Memory	2x DDR5, up to 128GB, up to 8,400MT/s (OC)
Power delivery	10+2+1 phases
Graphics slot	PCIe 5.0 x16
M.2 slots	2 (both PCIe 5.0)
Networking	2.5Gb Ethernet, Wi-Fi 7, Bluetooth 5.4
Extras	Clear CMOS button, BIOS Flashback

Strengths and weaknesses

Pros

Two PCIe 5.0 M.2 slots on Mini-ITX
Strong power for its size
Wi-Fi 7
Premium build quality

Cons

Expensive for a B850 board
Fewer rear USB ports than larger boards
M.2 heatsink needs a screwdriver

Verdict

The ROG Strix B850-I packs two PCIe 5.0 M.2 slots, Wi-Fi 7 and strong power delivery into a tiny Mini-ITX board. It's the one to choose for a compact but powerful AM5 gaming PC. It earns our Best Mini-ITX award in our guide to the best motherboards.

Check price on Amazon →