ASUS PRIME B850M-A-CSM AM5 micro-ATX mATX Motherboard DDR5 256GB 3xM.2 PCIe5 (Boxed)
ASUS PRIME B850M-A-CSM: AM5 micro-ATX mATX board for Ryzen 7000/8000/9000. DDR5 to 256GB/8000+MHz(OC), 3x M.2(1xPCIe5), PCIe5 x16, 4xSATA, HDMI2.1/DP1.4, 2.5Gb LAN, Aura Sync.
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Discontinued
This item was discontinued and currently is not available for order on our website. The item may become available soon. Please contact us if you need more information regarding the upcoming arrivals.
| Motherboards - CPU Socket | AMD AM5 |
|---|---|
| Motherboards - Chipset | AMD B850 |
| Motherboards - Form Factor | Micro-ATX |
| Motherboards - Memory Type | DDR5 |
| Motherboards - Memory Profile Support | EXPO |
| Motherboards - Memory Slots | 4 |
| Motherboards - Max Memory Capacity | 256 GB |
| Motherboards - Main Slot PCIe Version | PCIe 5.0 |
| Motherboards - Color | Silver |
| Motherboards - M.2 Slots | 3 |
| Motherboards - SATA Ports | 4 |
| Motherboards - USB-C Support | None |
| Motherboards - RGB Headers | 3-pin 5V ARGB |
| Motherboards - Wireless Connectivity | None |
The ASUS PRIME B850M-A-CSM is a micro-ATX motherboard designed for AMD Ryzen 7000, 8000, and 9000 Series processors on the AM5 socket. Featuring the AMD B850 chipset, it delivers robust performance for gaming, content creation, and AI workloads with an 8+2+1 phase power design and six-layer PCB for stable power delivery.
It supports up to 256GB DDR5 across 4 DIMM slots (dual-channel, up to 8000+ MT/s OC) with AMD EXPO and ASUS AEMP profiles for easy overclocking. Storage options include 3x M.2 slots (1x PCIe 5.0 x4 up to 128Gbps, 2x PCIe 4.0 x4) and 4x SATA 6Gb/s ports with RAID 0/1/5/10. Expansion features a PCIe 5.0 x16 slot, plus additional PCIe 4.0 x16 slots. Connectivity includes 2.5Gb Ethernet, HDMI 2.1 (4K@60Hz), 2x DisplayPort 1.4 (8K@30Hz), multiple USB ports (up to 10Gbps), and 3x RGB headers for Aura Sync customization.
- ✅ AMD Ryzen 9000/8000/7000 Series ready
- ✅ DDR5-8000+ (OC), ECC/Non-ECC support
- ✅ PCIe 5.0 GPU + M.2 storage
- ✅ Comprehensive cooling: VRM/M.2/PCH heatsinks
- ✅ CSM features: ASUS Control Center Express
| Processor manufacturer | AMD |
| Processor socket | Socket AM5 |
| Compatible processor series | AMD Ryzen 7000 Series, AMD Ryzen 8000 Series, AMD Ryzen 9000 Series |
| Motherboard chipset | AMD B850 |
| Motherboard form factor | micro ATX |
| Supported memory types | DDR5-SDRAM |
| Number of memory slots | 4 |
| Memory slots type | DIMM |
| Memory channels | Dual-channel |
| ECC compatibility | ECC & Non-ECC |
| Supported memory clock speed (max) | 8000 MHz (OC) |
| Maximum internal memory | 256 GB |
| Number of M.2 (M) slots | 3 |
| 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 |
| Number of SATA III connectors | 4 |
| RAID levels | 0, 1, 5, 10 |
| PCI Express x16 (Gen 5.x) slots | 1 |
| PCI Express x16 (Gen 4.x) slots | 2 |
| USB 2.0 ports quantity | 4 |
| 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 |
| Ethernet LAN (RJ-45) ports | 1 |
| Ethernet interface type | 2.5 Gigabit Ethernet |
| HDMI ports quantity | 1 |
| HDMI version | 2.1 |
| DisplayPorts quantity | 2 |
| DisplayPort version | 1.4 |
| Number of RGB LED pin headers | 3 |
| Number of chassis fan connectors | 3 |
| Audio output channels | 7.1 channels |
| Product colour | Grey |
| Power source type | ATX |
| Windows operating systems supported | Windows 10 x64, Windows 11 |
| BIOS type | UEFI AMI |
| Package width | 275 mm |
| Package depth | 275 mm |
| Package height | 67.5 mm |
| Package weight | 1.45 kg |
| Width | 244 mm |
| Depth | 244 mm |
| Memory Profile Support | AMD EXPO, AEMP |