Overview of PCIe Lane Sharing on MSI B850 Motherboards
Motherboards
In a previous article, we covered PCIe lane sharing configurations for MSI X870E and X870 series motherboards. This article will focus on the PCIe bandwidth sharing design of MSI B850 series motherboards.
It is important to note that not all MSI B850 motherboards adopt a PCIe lane sharing design. Therefore, this article only includes B850 models featuring PCIe lane sharing, along with their respective lane configurations.
MPG B850 EDGE TI WIFI
PCIe / M.2 Specifications and Lane Sharing Overview
Below is a detailed breakdown of each slot, including its connection, supported speed, and any shared bandwidth configurations.
Slot / Port
Connected to
Speed Supported
Shares Bandwidth With
PCI_E1
CPU
PCIe 5.0 x16
No
PCI_E2
Chipset
PCIe 3.0 x1
No
PCI_E3
Chipset
PCIe 4.0 x4
M2_3
M2_1
CPU
PCIe 5.0 x4
No
M2_2
CPU
PCIe 5.0 x4
No
M2_3
Chipset
PCIe 4.0 x2
PCI_E3
M2_4
Chipset
PCIe 4.0 x4
No
PCIe Lane Sharing Notes:
- PCI_E3 and M2_3 share the chipset’s PCIe 4.0 x4 lanes.
MAG B850 TOMAHAWK MAX WIFI
PCIe / M.2 Specifications and Lane Sharing Overview
Slot / Port
Connected to
Speed Supported
Shares Bandwidth With
PCI_E1
CPU
PCIe 5.0 x16
No
PCI_E2
Chipset
PCIe 3.0 x1
No
PCI_E3
Chipset
PCIe 4.0 x4
M2_3
M2_1
CPU
PCIe 5.0 x4
No
M2_2
CPU
PCIe 5.0 x4
No
M2_3
Chipset
PCIe 4.0 x2
PCI_E3
M2_4
Chipset
PCIe 4.0 x4
No
PCIe Lane Sharing Notes:
- PCI_E3 and M2_3 share the chipset’s PCIe 4.0 x4 lanes.
B850 GAMING PLUS WIFI / B850 GAMING PLUS WIFI PZ
PCIe / M.2 Specifications and Lane Sharing Overview
Slot / Port
Connected to
Speed Supported
Shares Bandwidth With
PCI_E1
CPU
PCIe 5.0 x16
No
PCI_E2
Chipset
PCIe 3.0 x1
PCI_E3 & PCI_E4
PCI_E3
Chipset
PCIe 4.0 x4
PCI_E2 & PCI_E4
PCI_E4
Chipset
PCIe 3.0 x1
PCI_E2 & PCI_E3
M2_1
CPU
PCIe 5.0 x4
No
M2_2
CPU
PCIe 4.0 x4
No
M2_3
Chipset
PCIe 4.0 x2
No
PCIe Lane Sharing Notes:
- PCI_E2, PCI_E3 and PCI_E4 share the chipset’s PCIe 4.0 x4 lanes
PRO B850-P WIFI / PRO B850-VC WIFI / PRO B850-VC WIFI6E
PCIe / M.2 Specifications and Lane Sharing Overview
Slot / Port
Connected to
Speed Supported
Shares Bandwidth With
PCI_E1
CPU
PCIe 5.0 x16
No
PCI_E2
Chipset
PCIe 3.0 x1
PCI_E3 & PCI_E4
PCI_E3
Chipset
PCIe 4.0 x4
PCI_E2 & PCI_E4
PCI_E4
Chipset
PCIe 3.0 x1
PCI_E2 & PCI_E3
M2_1
CPU
PCIe 5.0 x4
No
M2_2
CPU
PCIe 4.0 x4
No
M2_3
Chipset
PCIe 4.0 x2
No
PCIe Lane Sharing Notes:
- PCI_E2, PCI_E3 and PCI_E4 share the chipset’s PCIe 4.0 x4 lanes
Note:
The configurations above apply when using AMD Ryzen 7000 and Ryzen 9000 series processors. For limitations regarding Ryzen 8000 series processors, please refer to the specific motherboard product webpage.
MSI X870E/X870/B850/B840 Gaming Motherboards: https://www.msi.com/Landing/amd-am5-x870e-x870-b850-b840-ryzen-9000-x3d-best-ai-gaming-motherboard
