ASUS PRIME B860M-A-CSM mATX Motherboard - LGA1851 DDR5
ASUS
ASUS PRIME B860M-A-CSM mATX Motherboard - LGA1851 DDR5
The ASUS PRIME B860M-A-CSM is a micro-ATX motherboard built for Intel Core Ultra Processors (Series 2) and DIY PC builders who want DDR5 memory, PCIe 5.0 storage, and robust power delivery without a large form factor. It combines stable power stages, fast M.2 connectivity, and comprehensive cooling to handle demanding workloads and AI applications.
Why this product
PCIe 5.0 M.2 slot with 128Gbps speed
One M.2 slot runs at full PCIe 5.0 x4 for the fastest NVMe drives; a second slot offers PCIe 4.0 x4 for additional storage.
7+1+1+1 power stages rated 80A each
Heavy-duty VRM design ensures stable voltage delivery to high-core-count processors and handles overclocking without compromise.
DDR5 with DIMM Fit memory tuning
Four DIMM slots support up to 256GB DDR5, and ASUS's DIMM Fit BIOS feature auto-optimises each module for maximum stability and speed.
Dual video output plus USB Type-C DP
Two DisplayPort and one HDMI port on the rear panel, plus a USB 20Gbps Type-C port with DisplayPort Alt Mode for flexible multi-monitor setups.
Comprehensive cooling with hybrid headers
VRM and M.2 heatsinks, plus three fan headers and an AIO pump header that can each sense three thermal zones for fine-grained temperature control.
- SocketIntel LGA1851
- ChipsetIntel B860
- Form FactorMicro-ATX (9.6 × 9.6 inch)
- Memory Slots4 × DIMM DDR5
- M.2 Slots2 (PCIe 5.0 x4, PCIe 4.0 x4)
- Rear USB8 ports (20Gbps USB-C, 10Gbps USB-A, 2× 5Gbps, 4× 2.0)
- Video Outputs2× DisplayPort, 1× HDMI, USB-C with DP Alt Mode
- SKUASU-2647
- EAN4711387819869
- Supports all Intel Core Ultra Processors (Series 2) with LGA1851 socket, including Turbo Boost 2.0 and Turbo Boost Max 3.0.
- Accepts DDR5 UDIMM and CUDIMM modules up to 8666+ MT/s (overclocked); supports Intel XMP and ASUS Enhanced Memory Profile III.
- Fits micro-ATX cases with 9.6 × 9.6 inch (24.4 × 24.4 cm) cutouts; smaller than standard ATX but larger than mini-ITX.
- The second PCIe x16 slot runs at x4 mode only; full-width dual-GPU setups will see reduced bandwidth on the second card.
- Not compatible with Intel 12th, 13th or 14th Gen Core processors, or AMD Ryzen CPUs—LGA1851 is exclusive to Core Ultra Series 2.
Best for
- AI PC builders and content creators
- Compact build enthusiasts
- Overclockers and tweakers
- Multi-monitor office and productivity setups
Trade-offs
- Users of older Intel processors
- AMD Ryzen PC builders
- Builders who need four full-speed PCIe x16 slots
- Those requiring Thunderbolt on the rear panel
ASUS PRIME series motherboards are expertly engineered to unleash the full potential of the latest Intel® Core™ Ultra Processors (Series 2). Boasting a robust power design, comprehensive cooling solutions and intelligent tuning options, the PRIME B860M-A-CSM motherboard provides users and PC DIY builders with a range of performance optimizations via intuitive software and firmware features. It's designed to be Advanced AI PC-ready, offering the power and connectivity needed for demanding AI applications.
Robust power design
Stable power is crucial for maximizing the performance of Intel® Core™ Ultra Processors (Series 2). The PRIME B860M-A-CSM is designed to meet the needs of high-core-count CPUs. It features 7(80A) + 1(80A) + 1(80A) + 1(80A) power stages that integrate high-side and low-side MOSFETs and drivers into packages rated for up to 80 amperes each.
Two M.2 slots (up to 128Gbps)
The PRIME B860M-A-CSM offers a total of two M.2 slots, including one that supports data-transfer speeds of up to 128Gbps via PCIe 5.0, one that supports 64Gbps via PCIe 4.0.
AEMP III for Ultimate DDR5 Performance
DIMM Fit is an ASUS-exclusive BIOS feature that precisely analyzes individual memory modules to optimize performance and pinpoint potential issues.
Cooler by design
The PRIME B860M-A-CSM motherboard is engineered with multiple onboard heatsinks and an array of hybrid fan headers to help ensure your rig stays cool and stable under intense workloads. The massive VRM heatsinks and essential thermal pads improve heat transfer from the MOSFETs and chokes for better cooling performance. A dedicated PWM/DC header supports self-contained water-cooling setups. Each header can dynamically reference three thermal sensors. Fan Xpert 2+ lets you to map the temperature of supported ASUS graphics cards to optimize cooling for GPU- and CPU-intensive tasks.
USB 20Gbps port
The PRIME B860M-A-CSM motherboard offers a versatile range of connectivity, including support for the latest version of PCI Express and an arsenal of USB ports which includes Type-C connections. A batch of USB ports supports high-end rigs loaded with peripherals, including a rear USB Type-C® port with transmission speeds of up to 20Gbps.
DIY friendly
PCIe 5.0 is twice as fast as PCIe 4.0. ASUS has adapted our SMT manufacturing for the faster SafeSlot, a reinforced metal sheath that ensures secure card installation and faster data speeds. The Q-LED Core display produces color-coded lights during the Power-On Self-Test (POST) that can help you troubleshoot potential issues.
Aura Sync — Outshine the competition
ASUS Aura offers full RGB lighting control with a variety of functional presets for the built-in RGB LEDs as well as strips and devices connected to the onboard RGB headers — and it can all be synced with an ever-growing portfolio of Aura-capable hardware.
UEFI BIOS
The renowned ASUS UEFI BIOS provides everything you need to configure, tweak and tune your system. It offers intelligently simplified options for PC DIY beginners, as well as comprehensive features for seasoned veterans.
General
| Brand | ASUS |
|---|---|
| Model | PRIME B860M-A-CSM |
CPU & Memory
| Socket | LGA1851 |
|---|---|
| Supported Processors | Intel Core Ultra Processors (Series 2) with Turbo Boost 2.0 and Turbo Boost Max 3.0 |
| Memory Slots | 4 × DIMM |
| Memory Type | DDR5 UDIMM, CUDIMM |
| Max Memory | 256GB |
| Memory Speed | Up to 8666+ MT/s (overclocked) |
| Memory Features | Dual channel, DIMM Fit, Intel XMP, ASUS Enhanced Memory Profile III |
Storage & Expansion
| M.2 Slot 1 | Type 2242/2260/2280, PCIe 5.0 x4 (128Gbps), Key M |
|---|---|
| M.2 Slot 2 | Type 2242/2260/2280, PCIe 4.0 x4 (64Gbps), Key M |
| SATA Ports | 4 × 6Gb/s |
| PCIe Slots | 1× PCIe 5.0 x16 (CPU), 1× PCIe 4.0 x16 (x4 mode), 1× PCIe 4.0 x1 |
| Storage RAID | Intel Rapid Storage Technology RAID 0/1/5/10 |
Power & Cooling
| Power Stages | 7(80A) + 1(80A) + 1(80A) + 1(80A) |
|---|---|
| Power Connectors | 1× 24-pin main, 1× 8-pin +12V CPU |
| Fan Headers | 1× CPU Fan, 1× CPU OPT, 1× AIO Pump, 3× Chassis Fan (4-pin each) |
| Thermal Sensors | Each fan header can reference 3 thermal zones |
| Cooling Design | VRM heatsink, M.2 heatsink, thermal pads on MOSFETs and chokes |
Connectivity & Audio
| Rear USB Ports | 1× USB 20Gbps Type-C with DP Alt Mode, 1× USB 10Gbps Type-A, 2× USB 5Gbps Type-A, 4× USB 2.0 Type-A |
|---|---|
| Front USB Connectors | 1× USB 10Gbps Type-C header, 1× USB 5Gbps header (2 ports), 1× USB 2.0 header (2 ports) |
| Video Outputs | 2× DisplayPort 1.4 (4K@60Hz), 1× HDMI 2.1 (4K@60Hz), USB 20Gbps Type-C with DP video |
| Ethernet | 1× Realtek 2.5Gb with ASUS LANGuard |
| Audio | Realtek 7.1 Surround Sound HD CODEC, 24-bit/192 kHz, audio shielding, premium capacitors |
| Audio Connectors | 3× rear audio jacks, 1× front panel header, 1× S/PDIF out |
BIOS & Protection
| BIOS Type | UEFI AMI |
|---|---|
| BIOS Capacity | 256 Mb Flash ROM (128+128) |
| Protection Features | ASUS 5X PROTECTION III: DIGI+ VRM, ESD Guards, LANGuard, Overvoltage protection, SafeSlot, Stainless-steel back I/O |
| Diagnostic Features | Q-LED Core for POST troubleshooting |
Lighting & Design
| RGB Lighting | 1× Aura RGB header, 3× Addressable Gen 2 headers |
|---|---|
| Lighting Control | ASUS Aura Sync |
| I/O Shield | Pre-mounted stainless-steel |
| Form Factor | Micro-ATX, 9.6 × 9.6 inch (24.4 × 24.4 cm) |
Included & Compatibility
| Included Cables | 2× SATA 6Gb/s cables |
|---|---|
| Included Accessories | 1× M.2 rubber package, 1× M.2 screw package |
| Supported OS | Windows 11 (22H2 & later), Windows 10 64-bit (21H2 & later) |
Shipping
All our products are shipped from the United Kingdom within 24 to 48 hours of purchase. See our Shipping and Returns page for full details.
Returns
- Tech Syndicate offers a full money-back guarantee on all purchases made in our store. If you are not satisfied with your purchase, we will provide a full refund, no questions asked.
- Refunds are available within 45 days of delivery.
- After the 45-day period you are no longer eligible for a refund, so we encourage you to try the product within the first few weeks to make sure it fits your needs.