PCIe slots and adapters

Understanding the technical rules for PCIe adapters helps you correctly install and configure PCIe adapters in the system.

PCIe slots supported for different models

Table 1. PCIe slots supported and locations
Server rear and front view	Supported types and slot location
	Riser 1 assembly `1` Slot 1: PCIe 5 (x16, x8), full-height, half-length `2` Slot 2: PCIe 5 (x16, x8), low-profile Riser 2 assembly `3` Slot 3: PCIe 5 (x16), low-profile
	Riser 1 assembly `1` Slot 1: PCIe 5 (x16, x8), full-height, half-length `2` Slot 2: PCIe 5 (x16, x8), low-profile
	Riser 1 assembly `1` Slot 1: PCIe 5 (x16), full-height, half-length
	Riser 1 assembly `1` Slot 1: PCIe 5 (x16), full-height, half-length Riser 2 assembly `2` Slot 3: PCIe 5 (x16), full-height, half-length
	Riser 1 assembly `1` Slot 1: PCIe 5 (x16), full-height, half-length Riser 2 assembly `2` Slot 3: PCIe 5 (x16), low-profile
	Riser 1 assembly `1` Slot 1: PCIe 5 (x16), full-height, half-length
	Riser 3 assembly `1` Slot 4: PCIe 5 (x16), low-profile Riser 4 assembly `2` Slot 5: PCIe 5 (x16), full-height, half-length

When installing different types of PCIe adapters, refer to the following suggested installation priority:

Table 2. Recommended installation priority for different types of PCIe adapters
Installation priority
1. OCP module	2. InfiniBand adapter
3. Network adapter	4. Serial port (COM) bracket

Table 3. Recommended slot installation priority for PCIe adapters
Adapter type	Recommended slot installation priority	PCIe adapters
OCP module	Chassis with the front adapter assembly: slot 8 and 7 Chassis without the front adapter assembly: slot 6 and 7 Maximum quantity supported: 2	ThinkSystem Broadcom 57504 10/25GbE SFP28 4-Port OCP Ethernet Adapter ThinkSystem Broadcom 57508 100GbE QSFP56 2-Port OCP Ethernet Adapter ThinkSystem Broadcom 57414 10/25GbE SFP28 2-port OCP Ethernet Adapter ThinkSystem Mellanox ConnectX-6 Lx 10/25GbE SFP28 2-port OCP Ethernet Adapter
InfiniBand adapter	Slot 5 > Slot 4 > Slot 1 > Slot 2 > Slot 3 Maximum quantity supported: 5	ThinkSystem Nvidia ConnectX-7 NDR200/HDR QSFP112 2-port PCIe Gen5 x16 InfiniBand Adapter
NIC adapter	Slot 5 > Slot 4 > Slot 1 > Slot 2 > Slot 3 Maximum quantity supported: 5	ThinkSystem Broadcom 57414 10/25GbE SFP28 2-port PCIe Ethernet Adapter ThinkSystem Broadcom 57508 100GbE QSFP56 2-port PCIe 4 Ethernet Adapter ThinkSystem Mellanox ConnectX-6 Lx 10/25GbE SFP28 2-port PCIe Ethernet Adapter ThinkSystem Mellanox ConnectX-6 Dx 100GbE QSFP56 2-port PCIe Ethernet Adapter
NIC adapter	Slot 5 > Slot 1 > Slot 3 Maximum quantity supported: 3	ThinkSystem Broadcom 57504 10/25GbE SFP28 4-Port PCIe Ethernet Adapter

See this section to identify the correlations between the rear configuration and riser assemblies.

Table 4. Server rear configuration and riser assemblies¹
Server rear configuration	Riser 1 assembly	Riser 2 assembly
Figure 1. Three PCIe slots	Figure 2. LP-FH riser bracket Figure 3. BF² riser card Figure 4. BF riser card	Figure 5. LP riser bracket Figure 6. LP riser card
Figure 7. Two PCIe slots	Figure 8. FH riser bracket 1 Figure 9. FH riser card	Figure 10. FH riser bracket 2 Figure 11. FH riser card
Figure 12. Two PCIe slots	Figure 13. LP-FH riser bracket Figure 14. BF² riser card Figure 15. BF riser card	Riser 2 assembly is not supported.
Figure 16. Two PCIe slots	Figure 17. FH riser bracket 3 Figure 18. FH riser card	Figure 19. LP riser bracket Figure 20. LP riser card
Figure 21. One PCIe slot	Figure 22. FH riser bracket 3 Figure 23. FH riser card	Riser 2 assembly is not supported.
Figure 24. One PCIe slot	Figure 25. FH riser bracket 3 Figure 26. FH riser card	Riser 2 assembly is not supported.

Note

The illustrations of riser brackets and cards may look slightly different from the physical ones.
BF: “butterfly”, a riser card with slots on both sides.

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