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ASUS Prime B550M-A AC AMD AM4 (3rd Gen Ryzen™) Micro ATX DDR4 Motherboard (PCIe 4.0, WiFi, ECC Memory, 1Gb LAN, HDMI 2.1/D-Sub, 4K@60HZ, Addressable Gen 2 RGB Header and Aura Sync)
ASUS

ASUS Prime B550M-A AC AMD AM4 (3rd Gen Ryzen™) Micro ATX DDR4 Motherboard

Bottom line: The ASUS Prime B550M-A AC AMD AM4 Micro ATX DDR4 Motherboard ($97.72 on Amazon as of 2026-10-21 10:27 UTC): PCIe 4.0 x16 SafeSlot plus a PCIe 4.0 x4 M.2 for 3rd Gen Ryzen bandwidth; main trade-off: micro ATX layout limits you to fewer expansion slots than full ATX.

$97.72

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Buy on Amazon — $97.72 Compare to similar retro motherboards

By , Founder & Editor-in-Chief · Listing data updated

Mike Perry — Hardware researcher since 2014. For retro PC hardware and period-correct parts, synthesises manufacturer documentation, community compatibility lists and marketplace listings rather than first-hand lab testing. Core beat: GPU performance across gaming, rendering, and local-LLM inference.

*Price sourced from Amazon.com. Last updated 2026-10-21. Price and availability subject to change.

Pros & Cons

Pros

  • ✓ PCIe 4.0 x16 SafeSlot plus a PCIe 4.0 x4 M.2 for 3rd Gen Ryzen bandwidth
  • ✓ Dual M.2 slots let you run two NVMe SSDs without an add-in card
  • ✓ ECC memory support is rare at this micro ATX price point
  • ✓ HDMI 2.1 at 4K@60Hz alongside D-Sub and DVI for legacy monitors

Cons

  • ✗ Micro ATX layout limits you to fewer expansion slots than full ATX
  • ✗ 1Gb LAN only, so no 2.5Gb Ethernet for faster local transfers
  • ✗ USB 3.2 Gen 2 is Type-A; no front-panel Type-C header listed
  • ✗ B550 chipset means no overclocking headroom of an X570 board

Manufacturer description

The PCIe 4.0 x16 SafeSlot feeds a modern GPU full bandwidth, while dual M.2 slots let you run two NVMe SSDs with one wired for PCIe 4.0 x4 speeds. Connectivity is unusually broad for the segment: onboard WiFi, 1Gb LAN, USB 3.2 Gen 2 Type-A, and a display stack covering HDMI 2.1 at 4K@60Hz plus D-Sub and DVI, so you can drive a modern panel or a legacy monitor without an adapter. ASUS backs the layout with VRM and PCH heatsinks, hybrid fan headers, and the Fan Xpert 2 utility for tuning acoustics. OptiMem trace routing helps memory kits reach higher DDR4 frequencies at lower voltages, and ECC…

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SpecPicks Verdict

SpecPicks scored ASUS Prime B550M-A AC AMD AM4 Micro ATX DDR4 Motherboard using a rating × review-volume × price-fit model applied to published specs and reviews across the retro motherboards category. ASUS's retro motherboards lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.

Common buyer scenarios for retro motherboards of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.

Frequently Asked Questions

Which CPUs work with the ASUS Prime B550M-A AC?

It uses the AMD AM4 socket and is built for 3rd Gen AMD Ryzen processors. Support for other AM4 chips can depend on BIOS version, so check the ASUS CPU support list for your exact model before buying.

Does this board support PCIe 4.0 for a modern GPU and SSD?

Yes. It has one PCIe 4.0 x16 SafeSlot for your graphics card and dual M.2 slots, one of which runs PCIe 4.0 x4 for a fast NVMe SSD.

Does the ASUS Prime B550M-A AC have built-in WiFi?

Yes, WiFi is onboard along with 1Gb LAN, so you can build without adding a wireless card. The model's AC suffix denotes the integrated wireless.

Can I use it with an old monitor that only has VGA or DVI?

Yes. The rear I/O includes D-Sub (VGA) and DVI alongside HDMI 2.1, which outputs 4K at 60Hz. That mix makes it useful for retro builds and modern displays alike.

Does it really support ECC memory?

ECC memory is listed among its features, and ASUS OptiMem trace layout helps DDR4 kits run at higher frequencies with lower voltages. Confirm ECC behavior with your specific CPU and memory kit on the ASUS QVL.

Key Features

  • AMD AM4 Socket and PCIe 4.0: The perfect pairing for 3rd Gen AMD Ryzen CPUs
  • Ultrafast Connectivity: 1x PCIe 4.0 x16 SafeSlot, WiFi, 1Gb LAN, dual M.2 slots (NVMe SSD)—one with PCIe 4.0 x4 connectivity, USB 3.2 Gen 2 Type-A , HDMI 2.1 (4K@60HZ), D-Sub & DVI
  • Comprehensive Cooling: VRM heatsink, PCH heatsink, hybrid fan headers and Fan Xpert 2 utility
  • 5X Protection III: all-round protection with LANGuard, DRAM overcurrent protection, overvoltage protection, SafeSlot Core safeguards and stainless-steel back I/O
  • Boosted Memory Performance: ASUS OptiMem proprietary trace layout allows memory kits to operate at higher frequencies with lower voltages to maximize system performance.

Full Specifications

SizeB550M-A AC|M.2x2|D4|WiFi5
BrandASUS
ModelB550M-A AC
Warranty3 Years
UnitCount1
ReleaseDate2021-07-17T00:00:01Z
ManufacturerASUS
ItemPartNumberPRIME B550M-A AC
Full listing titleASUS Prime B550M-A AC AMD AM4 (3rd Gen Ryzen™) Micro ATX DDR4 Motherboard (PCIe 4.0, WiFi, ECC Memory, 1Gb LAN, HDMI 2.1/D-Sub, 4K@60HZ, Addressable Gen 2 RGB Header and Aura Sync)

Ready to buy?

ASUS Prime B550M-A AC AMD AM4 (3rd Gen Ryzen™) Micro ATX DDR4 Motherboard (PCIe 4.0, WiFi, ECC Memory, 1Gb LAN, HDMI 2.1/D-Sub, 4K@60HZ, Addressable Gen 2 RGB Header and Aura Sync) is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.

Buy on Amazon — $97.72

*Price sourced from Amazon.com. Last updated 2026-10-21. Price and availability subject to change.

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ASUS Prime B550M-A AC AMD AM4 (3rd Gen Ryzen™) Micro ATX DDR4 Motherboard (PCIe 4.0, WiFi, ECC Memory, 1Gb LAN, HDMI 2.1/D-Sub, 4K@60HZ, Addressable Gen 2 RGB Header and Aura Sync)
$97.72
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