Asus Prime B860-Plus VS Asus Prime B860M-K

Both the Asus Prime B860-Plus and the Asus Prime B860M-K share the same fundamental platform: the LGA 1851 socket paired with Intel's B860 chipset, meaning they target the same generation of processors with identical compatibility. They also match on several quality-of-life features — both support easy overclocking, include dual BIOS and easy BIOS reset, offer RGB lighting, and carry a 3-year warranty. Neither board includes integrated graphics, Wi-Fi, or Bluetooth, so users will need to factor in a discrete GPU and, if wireless connectivity is needed, a separate adapter or card.

The single defining differentiator in this group is form factor. The B860-Plus is a full ATX board (305 × 244 mm), while the B860M-K is a Micro-ATX board (244 × 222 mm), making it noticeably smaller in both dimensions. In practice, this means the B860M-K fits into more compact cases and is the natural choice for space-constrained or smaller desktop builds. The B860-Plus, by contrast, demands a standard mid-tower or full-tower enclosure but in return typically offers more physical room for expansion slots, VRM cooling, and cable management — advantages that become relevant when you examine the feature-specific spec groups.

For this general-info group alone, neither board has a clear overall edge on capability — the specs that matter most here are identical. The choice comes down entirely to build size: pick the B860-Plus if you are building in a standard ATX case and may want the headroom that a larger PCB affords, or the B860M-K if a smaller footprint is a priority and your case does not accommodate full ATX.

The memory specifications of the Asus Prime B860-Plus and Asus Prime B860M-K show a few key differences. The B860-Plus supports a maximum memory capacity of 256GB, whereas the B860M-K is limited to 128GB of maximum memory. Both motherboards support DDR5 memory, and they each have dual memory channels, which should provide similar memory performance in terms of bandwidth.

In terms of memory slots, the B860-Plus offers 4 slots, allowing for greater flexibility in expanding memory, while the B860M-K has only 2 slots. As for overclocked RAM speeds, the B860-Plus supports a speed of 8666 MHz, while the B860M-K supports a slightly higher 8800 MHz. Neither motherboard supports ECC memory.

Despite these differences, both motherboards support the same DDR memory version (DDR5) and memory channels, and neither offers support for ECC memory, making them comparable in that regard.

The Asus Prime B860-Plus and Asus Prime B860M-K offer similar port configurations, but with some differences in the number and types of USB ports. The B860-Plus has 2 USB 3.2 Gen 2 (USB-A) ports, 1 USB 3.2 Gen 1 (USB-A) port, and 2 USB 2.0 ports, whereas the B860M-K has only 1 USB 3.2 Gen 2 (USB-A) port, 2 USB 3.2 Gen 1 (USB-A) ports, and 3 USB 2.0 ports. Both motherboards lack USB 3.2 Gen 2x2, USB 4, Thunderbolt, and eSATA ports.

In terms of video outputs, both motherboards offer 1 HDMI output and 1 DisplayPort output. However, the B860-Plus has no VGA connector, while the B860M-K also lacks a VGA connector but includes a PS/2 port, which is absent on the B860-Plus.

Both motherboards include an RJ45 port for networking and support USB Type-C, but the B860M-K has more USB 2.0 ports compared to the B860-Plus, and the B860-Plus provides slightly more flexibility with its USB 3.2 Gen 2 (USB-A) ports.

The Asus Prime B860-Plus and Asus Prime B860M-K share several connectors, but there are differences in their configuration. Both motherboards offer the same number of USB 3.2 Gen 1 ports (through expansion) with 2 ports, and the same number of USB 2.0 ports (through expansion) with 4 ports. Additionally, they both provide 4 SATA 3 connectors, 2 USB 3.0 ports (through expansion), and have no SATA 2 connectors.

One key difference is in the number of fan headers; the B860-Plus has 6 fan headers, while the B860M-K has only 3 fan headers. The B860-Plus also has 3 M.2 sockets, compared to the B860M-K's 2 M.2 sockets, offering more expansion options for high-speed storage.

Both motherboards include a TPM connector and lack mSATA connectors and U.2 sockets, meaning their expansion capabilities for certain storage devices are similar in that regard.

The Asus Prime B860-Plus and Asus Prime B860M-K offer different configurations of expansion slots. The B860-Plus features 1 PCIe 4.0 x16 slot and 1 PCIe 5.0 x16 slot, while the B860M-K only provides 1 PCIe 4.0 x16 slot and no PCIe 5.0 x16 slots. The B860M-K also includes 2 PCIe x1 slots, which the B860-Plus lacks.

Neither motherboard offers PCI slots, PCIe 2.0 x16 slots, PCIe x4 slots, or PCIe x8 slots, keeping the available expansion options relatively simple and focused on PCIe x16 slots.

In summary, the main difference between the two is the B860-Plus's support for PCIe 5.0, while the B860M-K provides additional PCIe x1 slots for more flexibility in smaller expansion cards.

Both the Asus Prime B860-Plus and Asus Prime B860M-K offer identical audio specifications. Both motherboards support 7.1 audio channels, providing a rich sound experience. They also lack an S/PDIF Out port, which means neither product supports this digital audio connection. Additionally, both motherboards feature 3 audio connectors, offering standard options for connecting audio devices.

Since all the audio specs match, the two products are essentially the same in terms of their audio capabilities.

The Asus Prime B860-Plus and Asus Prime B860M-K both offer identical RAID support. Both motherboards support RAID 1, RAID 10 (1+0), and RAID 5, providing various options for data redundancy and performance optimization. Neither motherboard supports RAID 0+1, which is a mirrored RAID level with striped disks.

Since the RAID features are the same on both motherboards, there are no differences in storage configurations between the two models in this regard.