# Motherboard ASRock B850M Pro-A micro ATX — AMD B850, Socket AM5, DDR5, 4 DIMM, 256GB, 3x M.2, PCIe 5.0 x16, 2.5Gb LAN, HDMI 2.1, DisplayPort 1.4

**URL:** https://aio.lv/en/product--asrock-90-mxbr8-a0uayz--11247610
**Data updated:** 2026-01-21 11:08 (EET)
**Category:** Motherboards
**Manufacturer:** ASROCK
**Manufacturer code:** 90-MXBR8-A0UAYZ
**EAN:** 4711581490390
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 120.49 €
**Prices and availability valid until:** 2026-07-24 23:59
**Price without VAT (21%):** 99.58 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--asrock-90-mxbr8-a0uayz--11247610

## 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

ASRock B850M Pro-A is a micro ATX motherboard for Socket AM5 AMD Ryzen 9000 CPUs. It supports DDR5 memory (4 DIMM, up to 256 GB, dual-channel, ECC & non-ECC), three M.2 slots (PCIe 5.0/4.0 support), one PCIe 5.0 x16 slot, four SATA III ports and RAID 10. Integrated Realtek ALC897 7.1 audio, Dragon RTL8125BG 2.5Gb Ethernet, HDMI 2.1 and DisplayPort 1.4 provide modern connectivity. Ideal for compact gaming and workstation builds.

## Long description

The Asrock B850M Pro-A is a micro ATX motherboard with the AMD B850 chipset and Socket AM5, designed for AMD Ryzen 7000, 8000 and 9000 series processors. It supports up to 256 GB of DDR5 memory across four DIMM slots, offers PCIe 4.0 and PCIe 5.0 M.2 storage options, SATA III ports and multiple USB Type-A and Type-C connectors. The board includes reinforced PCIe slots, integrated 2.5 Gb/s LAN and onboard RGB headers, providing a balance of stability, connectivity and expandability for everyday computing and enthusiast builds.
Advantages
The motherboard features an 8+2+1 optimized VRM design with Dr. MOS integrated power stages for smooth and efficient CPU power delivery, a Hi-Density power connector for better overclocking stability, and a 6-layer PCB that improves signal integrity and thermal performance for memory overclocking. Storage options include PCIe Gen5 M.2 support and Hyper M.2 Gen4 x4 slots for high-speed NVMe drives. Cooling is aided by aluminum heatsinks, PWM/DC fan headers and ASRock's Fan-Tastic Tuning for automated fan curve setup. Connectivity options include Dragon 2.5 Gb/s LAN and multiple display outputs (HDMI + DisplayPort). Onboard RGB and SignalRGB support enable unified lighting control. Utilities such as Auto Driver Installer and BIOS Flashback simplify setup and updates.
Suitable for
Home and office desktop builds
Mid-range gaming systems with modern Ryzen CPUs
Content creation and streaming with high-speed storage needs
Systems requiring DDR5 memory and overclocking support
Key specifications
Form factor: Micro ATX
Chipset: AMD B850
Socket: AM5 (supports Ryzen 7000/8000/9000 series)
Memory: 4 x DIMM, DDR5 up to 256 GB
PCIe: PCIe 5.0 M.2 support and PCIe 4.0 M.2 (Hyper M.2 Gen4 x4)
Storage interfaces: SATA III, M.2 (NVMe)
LAN: Dragon 2.5 Gb/s Ethernet
Display outputs: HDMI and DisplayPort
Power phases: 8+2+1 VRM with Dr. MOS and Hi-Density power connector
How to use
Install the motherboard into a compatible micro ATX chassis and connect the AMD Socket AM5 CPU, DDR5 memory modules, and storage devices to the appropriate M.2 or SATA connectors. Attach the power supply using the Hi-Density CPU and ATX power connectors. Connect case fans to the PWM/DC headers and configure fan curves using ASRock Fan-Tastic Tuning in the UEFI or software. For initial setup, connect LAN and a display (HDMI or DisplayPort) and use the Auto Driver Installer if needed. If a BIOS update is required, use BIOS Flashback with a USB drive and power supply according to the manual.
Usage recommendations
Use DDR5 modules that support Intel XMP/AMD EXPO profiles for easier memory overclocking setup; ensure adequate cooling for heavy workloads and follow the motherboard manual for correct power connector installation and BIOS update procedures.

## Specifications

### Features

| Feature | Value |
|---|---|
| Motherboard form factor | Micro ATX |
| Motherboard chipset | AMD B850 |
| Component for | PC |
| Certification | FCC, CE, ErP/EuP |
| Audio output channels | 7.1 |
| Windows operating systems supported | Windows 11 x64, Windows 10 x64 |
| Motherboard chipset family | AMD |

| Feature | Value |
|---|---|
| Product colour | Black |

### 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 |
| ECC сompatibility | ECC & non-ECC |

### Expansion slots

| Feature | Value |
|---|---|
| Number of M.2 (M) slots | 3 |
| PCI Express x4 (Gen 4.x) slots | 1 |
| 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 |
| 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 |

### Graphics

| Feature | Value |
|---|---|
| Maximum resolution | 3840 x 2160 |
| Parallel processing technology support | Not supported |
| HDCP | Yes |

### Network

| Feature | Value |
|---|---|
| Ethernet LAN | Yes |
| LAN controller | Dragon RTL8125BG |
| Wi-Fi | No |
| Ethernet interface type | 2.5 Gigabit Ethernet |

### Internal I/O

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

### Rear panel I/O ports

| Feature | Value |
|---|---|
| Line-in | Yes |
| USB connector type | USB Type-C, USB Type-A |
| USB 2.0 ports quantity | 4 |
| Ethernet LAN (RJ-45) ports | 1 |
| Headphone outputs | 3 |
| Microphone in | Yes |
| HDMI ports quantity | 1 |
| HDMI version | 2.1 |
| DisplayPorts quantity | 1 |
| 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 | 1 |
| USB 3.2 Gen 2 (3.1 Gen 2) Type-C ports quantity | 1 |

### Storage controllers

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

### 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 |
|---|---|
| Supported processor sockets | Socket AM5 |
| DisplayPort version | 1.4 |
| Audio chip | Realtek ALC897 |

### Packaging content

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

## FAQ

### How much does the ASRock B850M Pro-A micro ATX motherboard cost, and is it available for purchase?

The price is 120.49 € (valid at the time of publication and already includes all taxes). The item is available for order — 132 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 ASRock B850M Pro-A micro ATX motherboard 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 ASROCK 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 ASROCK 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 ASRock B850M Pro-A micro ATX motherboard?

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/11247610/65439664_large.webp