# Motherboard ASUS PRIME B850M-A-CSM AMD B850 Socket AM5 micro ATX, DDR5, 4 DIMM, 256 GB, PCIe 4.0/5.0, 2.5Gb LAN

**URL:** https://aio.lv/en/product--asus-prime-b850m-a-csm--11458599
**Data updated:** 2026-03-01 12:08 (EET)
**Category:** Motherboards
**Manufacturer:** Asus
**Manufacturer code:** PRIME B850M-A-CSM
**EAN:** 4711636054720
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 195.99 €
**Prices and availability valid until:** 2026-07-24 23:59
**Price without VAT (21%):** 161.98 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--asus-prime-b850m-a-csm--11458599

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 09.07.2026 | free |
| Pickup points | 14.07.2026 | 1.89 EUR |
| Courier delivery to door | 14.07.2026 | 4.99 EUR |

## Summary description

The ASUS PRIME B850M-A-CSM is a micro ATX motherboard with AMD B850 chipset and Socket AM5, compatible with AMD Ryzen 7000/8000/9000 series CPUs. It supports DDR5 memory across 4 DIMM slots up to 256 GB, offers PCIe 4.0 and 5.0 interfaces for storage, RAID 0/1/5/10 support, and a 2.5 Gigabit Ethernet port. Suitable for building compact desktops, workstations or upgrade projects requiring modern connectivity and high memory capacity.

## Long description

ASUS PRIME B850M-A-CSM is a micro ATX motherboard based on the AMD B850 chipset with Socket AM5, designed for compact desktop systems and small workstations. The board supports AMD Ryzen 7000/8000/9000 series processors and offers four DDR5 DIMM slots that accept up to 256 GB of memory. Expansion and storage are served by PCIe 4.0 and PCIe 5.0 interfaces, multiple USB ports and integrated 2.5 Gigabit Ethernet, while integrated display output support allows resolutions up to 7680×4320.
Advantages
The PRIME B850M-A-CSM combines a space-saving micro ATX layout with modern connectivity: support for DDR5 memory across four DIMM slots, PCIe 5.0 lanes for next-generation NVMe SSDs and PCIe 4.0 for legacy cards. Integrated 2.5Gb LAN provides faster wired networking compared with standard Gigabit solutions, and onboard display outputs support high-resolution monitors. RAID 0/1/5/10 support adds flexible storage configuration options. The board includes a full set of USB ports and audio channels suitable for typical office and development tasks.
Suitable for
 Compact desktop PCs and small form-factor workstations
 Office and business systems requiring reliable wired networking
 Content creation or light multimedia work with high-resolution displays
 Systems needing DDR5 memory and future-proof PCIe 5.0 storage
Key specifications
 Form factor: Micro ATX
 Chipset: AMD B850
 Processor socket: Socket AM5 (compatible with Ryzen 7000/8000/9000 series)
 Memory: 4 × DDR5 DIMM slots, up to 256 GB
 Storage/expansion interfaces: PCIe 5.0 and PCIe 4.0 support for NVMe SSDs and expansion cards
 Networking: Integrated 2.5 Gigabit Ethernet
 Audio: Multi-channel audio (up to 7.1 channels)
 Display output: HDMI output supporting up to 7680×4320 resolution
 Rear I/O: USB 2.0 ports, USB 3.2 Gen 1 Type-A ports, USB 3.2 Gen 2 Type-A ports, RJ-45 Ethernet
How to use
Install a compatible Socket AM5 AMD Ryzen processor and secure it according to the CPU installation instructions. Populate the DDR5 DIMM slots with matched memory modules up to the supported total of 256 GB, following the recommended slot population for dual- or quad-channel operation. Connect storage devices to the appropriate PCIe or SATA interfaces and configure RAID 0/1/5/10 if required through the firmware utility. Attach power connectors from a compatible PSU, connect display and network cables, and install an operating system with updated chipset drivers for optimal performance.
Usage recommendations
For stable operation and maximum performance, use high-quality DDR5 memory modules matched in capacity and frequency, a power supply that meets system power requirements, and the latest BIOS and chipset drivers from the manufacturer. When using PCIe 5.0 NVMe storage, ensure proper cooling for sustained workloads and consult the motherboard manual for recommended slot occupations and BIOS settings.

## Specifications

### Features

| Feature | Value |
|---|---|
| Motherboard form factor | Micro ATX |
| Motherboard chipset | AMD B850 |
| Component for | PC |
| Audio output channels | 7.1 |
| Cooling type | Passive |
| Windows operating systems supported | Windows 11, Windows 10 x64 |
| Motherboard chipset family | AMD |
| Power source type | ATX |

| Feature | Value |
|---|---|
| Product colour | Grey |

### Processor

| Feature | Value |
|---|---|
| Processor manufacturer | AMD |
| Processor socket | Socket AM5 |

### Memory

| Feature | Value |
|---|---|
| Number of memory slots | 4 |
| Maximum internal memory | 256 GB |
| Supported memory types | DDR5-SDRAM |
| Memory channels | Dual-channel |
| Unbuffered memory | Yes |
| Memory slots type | DIMM |
| Supported memory clock speed (max) | 8000 MHz |
| Maximum internal memory per slot | 64 GB |
| ECC сompatibility | ECC & non-ECC |

### Expansion slots

| Feature | Value |
|---|---|
| Number of M.2 (M) slots | 3 |
| PCI Express x16 (Gen 4.x) slots | 2 |
| PCI Express x16 (Gen 5.x) slots | 1 |
| 1st M.2 largest key size | 2280 |
| 2nd M.2 largest key size | 2280 |
| 3rd M.2 largest key size | 2280 |
| 4th M.2 largest key size | 2280 |
| 1st M.2 highest PCI Express generation | 5.0 |
| 2nd M.2 highest PCI Express generation | 4.0 |
| 3rd M.2 highest PCI Express generation | 4.0 |
| 4th M.2 highest PCI Express generation | 4.0 |

### Graphics

| Feature | Value |
|---|---|
| Maximum resolution | 7680 x 4320 |
| Parallel processing technology support | Not supported |

### Network

| Feature | Value |
|---|---|
| Ethernet LAN | Yes |
| Wi-Fi | No |
| Ethernet interface type | 2.5 Gigabit Ethernet |

### Internal I/O

| Feature | Value |
|---|---|
| USB 2.0 connectors | 2 |
| S/PDIF out connector | Yes |
| CPU fan connector | Yes |
| Number of COM connectors | 1 |
| ATX Power connector (24-pin) | Yes |
| Chassis intrusion connector | Yes |
| Number of chassis fan connectors | 3 |
| Front panel audio connector | Yes |
| TPM connector | Yes |
| Peripheral (Molex) power connectors (4-pin) | 1 |
| EPS power connector (8-pin) | Yes |
| USB 3.2 Gen 1 (3.1 Gen 1) connectors | 2 |
| Number of SATA III connectors | 4 |
| Front panel connector | Yes |
| 12V power connector | Yes |
| RGB LED pin header | Yes |
| Number of RGB LED pin headers | 3 |
| Number of CPU fan connectors | 1 |
| Number of EPS power connectors (8-pin) | 1 |

### Rear panel I/O ports

| Feature | Value |
|---|---|
| Line-in | Yes |
| USB 2.0 ports quantity | 4 |
| Ethernet LAN (RJ-45) ports | 1 |
| Headphone outputs | 1 |
| Microphone in | Yes |
| HDMI ports quantity | 1 |
| HDMI version | 2.1 |
| DisplayPorts quantity | 2 |
| USB 3.2 Gen 1 (3.1 Gen 1) Type-A ports quantity | 2 |
| USB 3.2 Gen 2 (3.1 Gen 2) Type-A ports quantity | 2 |

### Storage controllers

| Feature | Value |
|---|---|
| RAID levels | 1, 5, 10 |
| Supported storage drive types | HDD & SSD |
| RAID support | Yes |
| Number of storage drives supported | 7 |
| Supported storage drive interfaces | PCI Express 5.0, PCI Express 4.0 |

### BIOS

| Feature | Value |
|---|---|
| BIOS memory size | 256 Mbit |
| BIOS type | UEFI AMI |

### Weight & dimensions

| Feature | Value |
|---|---|
| Width | 244 mm |
| Depth | 244 mm |

### Other features

| Feature | Value |
|---|---|
| Number of HDDs supported | 4 |
| Supported processor sockets | Socket AM5 |
| Package weight | 1450 g |
| DisplayPort version | 1.4 |

### Packaging content

| Feature | Value |
|---|---|
| Cables included | SATA |
| Screws included | Yes |

### Packaging data

| Feature | Value |
|---|---|
| Package depth | 275 mm |
| Package height | 67.5 mm |
| Package width | 275 mm |

## FAQ

### How much does the Motherboard ASUS PRIME B850M-A-CSM cost, and is it available for purchase?

The price is 195.99 € (valid at the time of publication and already includes all taxes). The item is available for order — 24 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 09.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay, Installment. All transactions are 100% secure and encrypted.

### Can Motherboard ASUS PRIME B850M-A-CSM be purchased with a lease?

Yes, the purchase is available both on credit and with an interest-free installment plan. Learn more about installments and credit options: https://aio.lv/en/payment#b3

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All Asus products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized Asus service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

### How can I tell if this product suits my needs?

When making a choice, we recommend paying attention to the key features: motherboard form factor, motherboard chipset, component for, processor socket, number of memory slots, maximum internal memory, supported memory types, compatibility with your devices or usage conditions, material quality, functionality, and warranty terms. These characteristics will help you determine how well the model meets your needs.

### Where can I download the instructions for Motherboard ASUS PRIME B850M-A-CSM?

You can download the instructions in PDF format from the “Instructions” section on the product description page. The file contains complete information about installation, setup, and usage.

## Image

https://aio.lv/img/cache/product/11458599/66135665_large.webp