ASUS PRIME B850M-A WIFI-CSM – Entry-Level AM5 Motherboard

About the ASUS PRIME B850M-A 

The PRIME B850M-A targets value-focused builders entering AMD's AM5 platform. This micro ATX motherboard supports Ryzen 9000, 8000, and 7000 series processors with modern features that matter. It's designed for first-time builders and upgraders who want reliability without RGB overkill or extreme overclocking they'll never use.

What This PRIME B850M-A Motherboard Does for You

This AMD motherboard delivers solid performance for gaming and productivity work without premium pricing. The B850 chipset is AMD's newest mid-range option with PCIe 5.0 storage support. Three M.2 slots let you run multiple fast drives without cable mess or storage compromises. WiFi 6E means you skip ethernet cables for your PC build without speed penalties. The 2.5Gb LAN handles wired connections when you need stability for competitive gaming or file transfers.

Build Quality and DIY Features

ASUS's Q-Design features make this board beginner-friendly without feeling cheap. The pre-mounted I/O shield saves installation frustration. Q-LED diagnostic lights tell you exactly what's wrong if your build won't POST. BIOS FlashBack updates firmware without a CPU installed, crucial for newer Ryzen chip compatibility. VRM heatsinks keep your processor stable under gaming loads, even with Ryzen 9 9900X chips.

Perfect For

• Mid-range gaming builds with Ryzen 7 9700X or Ryzen 5 9600X paired with RTX 4070 graphics cards
• Compact micro ATX builds where space matters but performance stays strong
• First-time builders needing reliable components with helpful diagnostic features
• Office or productivity systems using Ryzen 8000 APUs with integrated graphics

Why Buy from Mansa Computers

• 3-year Singapore warranty with ASUS service support
• Fast WhatsApp inquiry response for compatibility questions
• Open 7 days a week for support and troubleshooting
• Home delivery available across Singapore

Technical Specifications Summary

Chipset
AMD B850

Socket
AM5 (Ryzen 9000/8000/7000)

Form Factor
Micro ATX (24.4cm × 24.4cm)

Memory
4× DDR5 slots, up to 256GB, 8000MT/s OC

Storage
3× M.2 PCIe (1× Gen5), 4× SATA

Networking
WiFi 6E, Bluetooth 5.3, 2.5Gb LAN

PCIe Slots
1× PCIe 5.0 x16, 1× PCIe 4.0 x16

USB
2× USB 10Gbps, 4× USB 5Gbps, 4× USB 2.0

Ready to build your next AMD system? The ASUS PRIME B850M-A WIFI-CSM delivers modern features at sensible pricing. Questions about CPU or RAM compatibility? Message us on WhatsApp anytime.

Model
PRIME B850M-A WIFI-CSM

CPU
AMD Socket AM5 for AMD Ryzen™ 9000 & 8000 & 7000 Series Desktop Processors*
* Refer to https://www.asus.com/support/download-center/ for CPU support list.

Chipset
AMD B850 Chipset

Memory
4 x DIMM slots, max. 256GB, DDR5 Supports up to 8000+MT/s (OC) with Ryzen™ 9000 & 8000 & 7000 Series Processors, ECC and Non-ECC Un-buffered DIMM*
Dual channel memory architecture
Supports AMD Extended Profiles for Overclocking (EXPO™)
ASUS Enhanced Memory Profile (AEMP)
* Supported memory types, data rate (speed), and number of DRAM modules vary depending on the CPU and memory configuration, for more information please refer to CPU/Memory Support list under the Support tab of product information site or visit https://www.asus.com/support/download-center/. Adjustments will be made based on the specifications of mass-produced memory products available on the market.
* Non-ECC, un-buffered DDR5 memory supports On-Die ECC function.

Graphics
2 x DisplayPort**
1 x HDMI™ port***
* Graphics specifications may vary between CPU types. Please refer to AMD CPU specifications.
** Supports max. 8K@30Hz as specified in DisplayPort 1.4.
*** Supports 4K@60Hz as specified in HDMI 2.1.
Expansion Slots
AMD Ryzen™ 9000 & 7000 Series Desktop Processors*
1 x PCIe 5.0 x16 slot (supports x16 mode)
AMD Ryzen™ 8000 Series Desktop Processors
1 x PCIe 4.0 x16 slot (supports x8/x4 mode)**
AMD B850 Chipset
1 x PCIe 4.0 x16 slot (supports x1 mode)
* Please check the PCIe bifurcation table on the support site (https://www.asus.com/support/FAQ/1037507/).
** Specifications vary by CPU types.
- To ensure compatibility of the device installed, please refer to https://www.asus.com/support/download-center/ for the list of supported

Storage
Supports 3 x M.2 slots and 4 x SATA 6Gb/s ports
AMD Ryzen™ 9000 & 7000 Series Desktop Processors
M.2_1 slot (Key M), type 2280 (supports PCIe 5.0 x4 mode)
M.2_2 slot (Key M), type 2280 (supports PCIe 4.0 x4 mode)
AMD Ryzen™ 8000 Series Desktop Processors
M.2_1 slot (Key M), type 2280 (supports PCIe 4.0 x4 mode)
M.2_2 slot (Key M), type 2280 (supports PCIe 4.0 x4/x2 mode)*
AMD B850 Chipset
M.2_3 slot (Key M), type 2242/2260/2280 (supports PCIe 4.0 x4 mode)
4 x SATA 6Gb/s ports
* Specifications vary by CPU types.
AMD RAIDXpert2 Technology
Ryzen™ 9000 Series Processors: RAID 0/1/5/10
Ryzen™ 8000 Series Processors: RAID 0/1
Ryzen™ 7000 Series Processors: RAID 0/1/10

Ethernet
1 x Realtek 2.5Gb Ethernet
ASUS LANGuard

Wireless & Bluetooth
Wi-Fi 6E
2x2 Wi-Fi 6E (802.11ax)
Supports 2.4/5/6GHz frequency band*
Bluetooth® v5.3**
* WiFi 6E 6GHz regulatory may vary between countries, supported only in Windows 11 or later.
** The Bluetooth® version may vary, please refer to the Wi-Fi module manufacturer's website for the latest specifications."

USB
Rear USB (Total 8 ports)
2 x USB 10Gbps ports (2 x Type-A )
2 x USB 5Gbps ports (2 x Type-A)
4 x USB 2.0 ports (4 x Type-A)
Front USB (Total 7 ports)
1 x USB 5Gbps connector (supports USB Type-C®)
1 x USB 5Gbps header supports 2 additional USB 5Gbps ports
2 x USB 2.0 headers support 4 additional USB 2.0 ports
* USB Type-C® power delivery output: max. 5V/3A

Audio
Realtek 7.1 Surround Sound High Definition Audio CODEC*
- Supports: Jack-detection, Multi-streaming, Front Panel Jack-retasking
- Supports up to 24-Bit/192 kHz playback
Audio Features
- Audio Shielding
- Premium audio capacitors
- Dedicated audio PCB layers
* A chassis with an HD audio module in the front panel is required to support 7.1 Surround Sound audio output.

Back Panel I/O Ports
2 x USB 10Gbps ports (2 x Type-A)
2 x USB 5Gbps ports (2 x Type-A)
4 x USB 2.0 ports (4 x Type-A)
2 x DisplayPort
1 x HDMI™ port
1 x Wi-Fi module
1 x Realtek 2.5Gb Ethernet port
3 x Audio jacks
1 x BIOS FlashBack™ button

Fan and Cooling Related I/O Connectors
1 x 4-pin CPU Fan header
1 x 4-pin CPU OPT Fan header
1 x 4-pin AIO Pump header
3 x 4-pin Chassis Fan headers

Power Related I/O Connectors
1 x 24-pin Main Power connector
1 x 8-pin +12V CPU Power connectors
1 x 4-pin +12V CPU Power connectors
Storage Related
3 x M.2 slots (Key M)
4 x SATA 6Gb/s ports

USB Connector I/O Connectors
1 x USB 5Gbps connector (supports USB Type-C® )
1 x USB 5Gbps header supports 2 additional USB 5Gbps ports
2 x USB 2.0 headers support 4 additional USB 2.0 ports

Miscellaneous I/O Connectors
3 x Addressable RGB Gen 2 headers
1 x Clear CMOS header
1 x Chassis Intrusion header
1 x COM Port header
1 x Front Panel Audio header (F_AUDIO)
1 x S/PDIF Out header
1 x SPI TPM header (14-1 pin)
1 x 10-1 pin System Panel header

Special Features
ASUS 5X PROTECTION III
- DIGI+ VRM
- LANGuard
- Overvoltage protection
- SafeSlot
- Stainless-steel back I/O
ASUS Q-Design
- Q-Antenna
- Q-Dashboard
- Q-DIMM
- Q-LED Core
- Q-Slot
ASUS Thermal Solution
- M.2 heatsink
- VRM heatsink design
ASUS EZ DIY
- BIOS FlashBack™ button
- BIOS FlashBack™ LED
- Pre-mounted I/O shield
- SafeSlot
Aura Sync
- Addressable RGB Gen 2 headers

ASUS Exclusive Software
ASUS AI Advisor
ASUS Driver Hub
ASUS GlideX
TurboV Core
ASUS CPU-Z
Norton 360 Deluxe (60 Days Free Trial)
WinRAR (40 Days Free Trial)
UEFI BIOS
Armoury Crate
- Aura Creator
- Aura Sync
- Fan Xpert 2+
ASUS EZ DIY
- ASUS CrashFree BIOS 3
- ASUS EZ Flash 3
- ASUS UEFI BIOS EZ Mode
- ASUS MyHotkey

BIOS
256 Mb Flash ROM, UEFI AMI BIOS

Manageability
WOL by PME, PXE

Accessories
2 x SATA 6Gb/s cables
1 x ASUS WiFi Q-Antenna
1 x M.2 rubber package
2 x Screw packages for M.2 SSD
1 x Quick start guide
1 x ACC Express activation key card

Operating System
Windows® 11, Windows® 10 64-bit

Form Factor
mATX Form Factor
9.6 inch x 9.6 inch (24.4 cm x 24.4 cm)

3 YEAR WARRANTY 

Avertek Enterprises Pte Ltd
25 Kallang Ave #03-03, Singapore 339416
Contact: 6341 7839

Ban Leong Technologies Ltd
150, #04-01 Ubi Ave 4, Ubi Biz-Hub,
Singapore 408825
Contact: 6512 9250

Frequently Asked Questions About ASUS PRIME B850M-A WIFI-CSM

Does the ASUS PRIME B850M-A support Ryzen 9000 CPUs out of the box?

Yes, B850 boards ship with BIOS support for Ryzen 9000 and 7000 series. If you need updates for future chips, use the BIOS FlashBack button without installing a CPU first.

What's the main difference between B850 and B650 chipsets?

B850 is AMD's newer mid-range chipset with improved USB and storage options. Both support the same CPUs, but B850 offers better future-proofing at similar pricing.

Can I use this micro ATX board in a standard ATX case?

Absolutely. Micro ATX boards fit perfectly in ATX cases without issues. You'll just have extra space, which actually helps with airflow and cable management.

What RAM speed works best with the ASUS PRIME B850M-A WIFI-CSM?

DDR5 6000MT/s is the sweet spot for Ryzen 9000 and 7000 CPUs. This board officially supports up to DDR5 8000MT/s with overclocking enabled in BIOS.

Is the 3-year warranty valid if I buy from Mansa Computers?

Yes, full 3-year ASUS Singapore warranty applies. If anything goes wrong, contact us directly or go through ASUS service centers. We help with any issues.

How long will it take to receive my purchase?

Standard Shipping - 3 to 5 days

Express Shipping - 1 to 2 days

Can I opt for store pickup?

Yes, we are open daily for collection from 11 AM - 6.30 PM.

Address: 1 Ubi View #01-22, Focus One Building Singapore 408555 (Door located nearest to carpark exit gantry) We will contact you once your order is ready for collection!