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ASRock B850 Pro-A
ASRock B850M Pro-A

ASRock B850 Pro-A ASRock B850M Pro-A

Overview

Welcome to our detailed specification comparison between the ASRock B850 Pro-A and the ASRock B850M Pro-A — two B850 chipset motherboards targeting AM5 builds at different scales. While they share a strong foundation of core features, key differences in form factor, expansion options, and connectivity make each board a distinct proposition. Read on to see how these two boards stack up across storage, ports, slots, and more.

Common Features

  • ✓ Both boards use the AM5 CPU socket.
  • ✓ Both boards feature the B850 chipset.
  • ✓ Wi-Fi is not available on either product.
  • ✓ Bluetooth is not available on either product.
  • ✓ Both boards include HDMI 2.1 output.
  • ✓ Overclocking support is available on both products.
  • ✓ Easy BIOS reset is not available on either product.
  • ✓ Dual BIOS is present on both products.
  • ✓ Both boards support a maximum memory amount of 256GB.
  • ✓ Both boards support overclocked RAM speeds up to 8000 MHz.
  • ✓ Both boards have 4 memory slots.
  • ✓ Both boards use DDR5 memory.
  • ✓ Both boards operate on 2 memory channels.
  • ✓ ECC memory is not supported on either product.
  • ✓ Both boards include 1 USB 3.2 Gen 2 USB-C port.
  • ✓ Neither board has USB 3.2 Gen 2x2, USB 4, or Thunderbolt ports.
  • ✓ Both boards have 1 RJ45 port.
  • ✓ Both boards include 4 SATA 3 connectors.
  • ✓ A TPM connector is present on both products.
  • ✓ Both boards have 1 PCIe 5.0 x16 slot.
  • ✓ Both boards offer 7.1 audio channels with 3 audio connectors.
  • ✓ S/PDIF Out is not available on either product.
  • ✓ Both boards support RAID 0, RAID 1, and RAID 10, but not RAID 5 or RAID 0+1.

Main Differences

  • • The form factor is ATX on the ASRock B850 Pro-A and Micro-ATX on the ASRock B850M Pro-A.
  • • RGB lighting is present on the ASRock B850 Pro-A but not available on the ASRock B850M Pro-A.
  • • The board width is 305 mm on the ASRock B850 Pro-A and 244 mm on the ASRock B850M Pro-A.
  • • USB 3.2 Gen 2 USB-A ports number 0 on the ASRock B850 Pro-A and 1 on the ASRock B850M Pro-A.
  • • USB 3.2 Gen 1 USB-A ports number 4 on the ASRock B850 Pro-A and 2 on the ASRock B850M Pro-A.
  • • A USB 3.2 Gen 1 USB-C port is present on the ASRock B850 Pro-A but not available on the ASRock B850M Pro-A.
  • • USB 2.0 ports number 6 on the ASRock B850 Pro-A and 4 on the ASRock B850M Pro-A.
  • • A DisplayPort output is not available on the ASRock B850 Pro-A but is present on the ASRock B850M Pro-A.
  • • USB 3.2 Gen 1 expansion ports number 2 on the ASRock B850 Pro-A and 4 on the ASRock B850M Pro-A.
  • • USB 2.0 expansion ports number 3 on the ASRock B850 Pro-A and 4 on the ASRock B850M Pro-A.
  • • Fan headers number 7 on the ASRock B850 Pro-A and 5 on the ASRock B850M Pro-A.
  • • USB 3.0 expansion ports number 2 on the ASRock B850 Pro-A and 4 on the ASRock B850M Pro-A.
  • • M.2 sockets number 4 on the ASRock B850 Pro-A and 3 on the ASRock B850M Pro-A.
  • • A PCIe 4.0 x16 slot is present on the ASRock B850 Pro-A but not available on the ASRock B850M Pro-A.
  • • A PCIe x4 slot is not available on the ASRock B850 Pro-A but is present on the ASRock B850M Pro-A.
Specs Comparison
ASRock B850 Pro-A

ASRock B850 Pro-A

ASRock B850M Pro-A

ASRock B850M Pro-A

General info:
CPU socket AM5 AM5
chipset B850 B850
form factor ATX Micro-ATX
release date January 2025 January 2025
supports Wi-Fi ✕ ✕
Has Bluetooth ✕ ✕
HDMI version HDMI 2.1 HDMI 2.1
Easy to overclock ✓ ✓
has RGB lighting ✓ ✕
Easy to reset BIOS ✕ ✕
Has dual BIOS ✓ ✓
CPU sockets 1 1
Has integrated graphics ✕ ✕
warranty period 3 years 3 years
height 244 mm 244 mm
width 305 mm 244 mm
Has integrated CPU ✕ ✕

Both the ASRock B850 Pro-A and B850M Pro-A share the same foundational platform: an AM5 socket with a B850 chipset, support for overclocking, dual BIOS protection, and a 3-year warranty. Neither board includes Wi-Fi, Bluetooth, or integrated graphics, so users on both will need to budget for a discrete GPU and, if needed, a wireless adapter or PCIe card for connectivity. The shared HDMI 2.1 output is a practical bonus for users who want a direct display connection without a GPU.

The defining difference between these two boards is form factor. The Pro-A is a full ATX board (305 × 244 mm), while the Pro-A M is Micro-ATX (244 × 244 mm). In practice, ATX gives you more PCIe slots, more room for VRM cooling, and greater compatibility with a wider range of cases. Micro-ATX trades that expansion headroom for a smaller footprint, making it the right choice for compact builds or smaller mid-tower cases. One additional note: the Pro-A includes RGB lighting, while the B850M Pro-A does not — a minor aesthetic point, but relevant for users building a themed system.

For most users the decision comes down to build size and expansion needs. If you want maximum slot availability and a larger chassis, the B850 Pro-A (ATX) has a clear structural edge. If you are targeting a smaller case or simply do not need the extra slots, the B850M Pro-A delivers the same core platform in a more compact package. Neither board holds a meaningful advantage in platform capability for this spec group — the edge is purely physical.

Memory:
maximum memory amount 256GB 256GB
overclocked RAM speed 8000 MHz 8000 MHz
memory slots 4 4
DDR memory version 5 5
memory channels 2 2
Supports ECC memory ✕ ✕

The ASRock B850 Pro-A and ASRock B850M Pro-A share identical memory specifications. Both support a maximum memory amount of 256GB and offer the same overclocked RAM speed of 8000 MHz. Each motherboard comes with 4 memory slots, supporting DDR5 memory and operating with 2 memory channels.

Neither motherboard supports ECC memory, meaning error-correcting code (ECC) RAM is not an option for either board. These memory specs are consistent across both models, offering the same memory capabilities and configurations.

Ports:
USB 3.2 Gen 2 ports (USB-A) 0 1
USB 3.2 Gen 1 ports (USB-A) 4 2
USB 3.2 Gen 2 ports (USB-C) 1 1
USB 3.2 Gen 1 ports (USB-C) 1 0
USB 2.0 ports 6 4
USB 3.2 Gen 2x2 ports 0 0
USB 4 40Gbps ports 0 0
USB 4 20Gbps ports 0 0
Thunderbolt 4 ports 0 0
Thunderbolt 3 ports 0 0
has an HDMI output ✓ ✓
DisplayPort outputs 0 1
RJ45 ports 1 1
Has USB Type-C ✓ ✓
eSATA ports 0 0
DVI outputs 0 0
has a VGA connector ✕ ✕
PS/2 ports 0 0

The ASRock B850 Pro-A and ASRock B850M Pro-A offer a range of USB ports, with some key differences in their configurations. The Pro-A includes 4 USB 3.2 Gen 1 ports (USB-A), 1 USB 3.2 Gen 2 port (USB-C), and 1 USB 3.2 Gen 1 port (USB-C), while the Pro-A M has 2 USB 3.2 Gen 1 ports (USB-A) and 1 USB 3.2 Gen 2 port (USB-A). Additionally, the Pro-A has 6 USB 2.0 ports, compared to 4 on the Pro-A M.

Both motherboards have an HDMI output and a single RJ45 port, but the Pro-A M adds a DisplayPort output, which the Pro-A lacks. Neither board offers USB 3.2 Gen 2x2, USB 4 40Gbps, USB 4 20Gbps, Thunderbolt 4, or Thunderbolt 3 ports, and both lack eSATA, DVI, and VGA connectors.

Both motherboards have USB Type-C support, with the Pro-A featuring 1 USB 3.2 Gen 2 (USB-C) and the Pro-A M offering 1 USB 3.2 Gen 2 (USB-C) and 0 USB 3.2 Gen 1 (USB-C). Neither model has PS/2 ports.

Connectors:
USB 3.2 Gen 1 ports (through expansion) 2 4
USB 2.0 ports (through expansion) 3 4
SATA 3 connectors 4 4
fan headers 7 5
USB 3.0 ports (through expansion) 2 4
M.2 sockets 4 3
Has TPM connector ✓ ✓
U.2 sockets 0 0
Has mSATA connector ✕ ✕
SATA 2 connectors 0 0

The ASRock B850 Pro-A and ASRock B850M Pro-A both offer similar connector setups but differ in a few key areas. Both motherboards feature 4 SATA 3 connectors, 7 fan headers on the Pro-A and 5 on the Pro-A M, and 3 M.2 sockets on the Pro-A M and 4 on the Pro-A. Both also support 2 USB 3.2 Gen 1 ports and 3 USB 3.0 ports (through expansion) on the Pro-A, while the Pro-A M offers 4 USB 3.2 Gen 1 and 4 USB 3.0 ports (through expansion).

Both models include a TPM connector, but neither offers mSATA connectors or U.2 sockets, and they both lack SATA 2 connectors. The Pro-A M has fewer USB 3.2 Gen 1 ports (through expansion) and fan headers compared to the Pro-A, which may impact expansion flexibility.

Overall, the Pro-A has more options for fan and USB expansion, while the Pro-A M trades some of those for a more compact design with slightly fewer connectors.

Expansion slots:
PCIe 4.0 x16 slots 1 0
PCIe 5.0 x16 slots 1 1
PCIe 3.0 x16 slots 0 0
PCIe x1 slots 0 0
PCI slots 0 0
PCIe 2.0 x16 slots 0 0
PCIe x4 slots 0 1
PCIe x8 slots 0 0

The ASRock B850 Pro-A and ASRock B850M Pro-A have different expansion slot configurations. The Pro-A includes 1 PCIe 4.0 x16 slot and 1 PCIe 5.0 x16 slot, whereas the Pro-A M offers 1 PCIe 5.0 x16 slot but lacks PCIe 4.0 x16. The Pro-A M includes 1 PCIe x4 slot, which the Pro-A does not have.

Both motherboards lack PCI slots, PCIe 2.0 x16 slots, and PCIe 3.0 x16 slots, so the expansion options are limited to PCIe 4.0 and 5.0 on the Pro-A, and PCIe 5.0 and x4 on the Pro-A M.

Overall, the Pro-A offers more flexibility in high-speed GPU expansion with PCIe 4.0 x16 support, while the Pro-A M adds an additional PCIe x4 slot but does not support PCIe 4.0 x16.

Audio:
audio channels 7.1 7.1
Has S/PDIF Out port ✕ ✕
audio connectors 3 3

The ASRock B850 Pro-A and ASRock B850M Pro-A both feature 7.1 audio channels, offering similar audio capabilities. Neither motherboard includes an S/PDIF Out port, and both have 3 audio connectors, so the audio output options are the same across both models.

There are no differences in the audio specifications between the two products, as both share identical features in terms of audio channels, connectors, and S/PDIF support.

Storage:
Supports RAID 1 ✓ ✓
Supports RAID 10 (1+0) ✓ ✓
Supports RAID 5 ✕ ✕
Supports RAID 0 ✓ ✓
Supports RAID 0+1 ✕ ✕

The ASRock B850 Pro-A and ASRock B850M Pro-A have identical storage features. Both motherboards support RAID 1, RAID 10 (1+0), and RAID 0. However, neither board supports RAID 5 or RAID 0+1, so their RAID capabilities are the same across both models.

In summary, there are no differences between the two products in terms of RAID support; both offer the same RAID configurations, including support for redundancy and performance-enhancing setups.

Comparison Summary & Verdict

Both the ASRock B850 Pro-A and ASRock B850M Pro-A are solid AM5 motherboards sharing the same B850 chipset, DDR5 memory support, PCIe 5.0 x16 slot, and RAID capabilities — making either a competent foundation for a modern build. The key decision comes down to size and expandability. The ASRock B850 Pro-A stands out with its ATX form factor, an extra M.2 socket (4 vs 3), a PCIe 4.0 x16 slot, more fan headers (7 vs 5), and RGB lighting — making it the stronger choice for full-tower or mid-tower builds that demand flexibility. The ASRock B850M Pro-A, on the other hand, suits compact builds with its Micro-ATX footprint, and it adds a DisplayPort output and a USB 3.2 Gen 2 USB-A port that the Pro-A lacks. Choose based on your case size and how much room to grow you need.

ASRock B850 Pro-A
Buy ASRock B850 Pro-A if...

Buy the ASRock B850 Pro-A if you want an ATX board with more M.2 sockets, an extra PCIe 4.0 x16 slot, more fan headers, and RGB lighting for a full-sized build with greater expansion headroom.

ASRock B850M Pro-A
Buy ASRock B850M Pro-A if...

Buy the ASRock B850M Pro-A if you need a compact Micro-ATX board that still delivers solid connectivity, including a DisplayPort output and a USB 3.2 Gen 2 USB-A port, in a smaller chassis.