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PCIe riser and adapter installation rules and order

PCIe risers and adapters must be installed in a specific order in your server.

The following illustration shows the server rear view with PCIe slots numbering.

Figure 1. PCIe slots
PCIe slots

The available PCIe slots depend on the risers and number of processors installed.

  • Riser A: x8x8 PCIe G4 Riser

  • Riser B: 2x8 & 4x16 PCIe G5 Riser

  • Riser C: 6x8 PCIe G5 Riser

Table 1. PCIe slot availability
Processor installed1 Riser 1 (A or B)2 Riser 2 (C)3 Riser 3 (A or B)
Two processors

  • A: slots 7, 8

  • B: slots 3, 6, 8

  • slots 11, 14

  • A: slots 19, 20

  • B: slots 15, 18, 20

Four processors

  • A: slots 7, 8

  • B: slots 3, 4, 5, 6, 7, 8

  • slots 9, 10, 11, 12, 13, 14

  • A: slots 19, 20

  • B: slots 15, 16, 17, 18, 19, 20

Note

  • PCIe slot 20 is unavailable for riser B when an M.2 drive assembly is installed.

  • PCIe slots 6 and 18 are unavailable for server models with E3.S bays.

  • Riser 2 is unavailable when the Processor Neptune® Core Module is installed.

  • PCIe slots 5 and 17 are unavailable for server models with E3.S bays and Processor Neptune® Core Module.

  • Performance may degrade when a x16 PCIe card is installed in a x8 lane PCIe slot.

PCIe riser installation rules and order​

Installation priorityPCIe riser typeRiser location priority
1x8x8 PCIe G4 Riser + M.2Riser 3
22x8 & 4x16 PCIe G5 Riser + M.2Riser 3
32x8 & 4x16 PCIe G5 RiserRiser 3, then riser 1
4x8x8 PCIe G4 RiserRiser 3, then riser 1
56x8 PCIe G5 RiserRiser 2

PCIe adapter installation rules and order​

The following table lists the recommended slot installation priority for common PCIe adapters.

Installation priorityComponentPCIe slot priority

1

  1. 16i RAID adapter

  2. 16i HBA adapter

  3. 8i RAID adapter

20, 8, 14, 11, 12, 18, 6, 15, 19

2

ThinkSystem NVIDIA ConnectX-7 NDR400 OSFP 1-Port PCIe Gen5 Adapter

7, 19, 18, 6, 16, 4

3

Double-wide GPU

18, 6, 16, 4

Single-wide GPU

18, 6, 16, 4, 3, 15, 5, 17

4

  • ThinkSystem Broadcom 57504 10/25GbE SFP28 4-Port PCIe Ethernet Adapter

  • ThinkSystem Mellanox ConnectX-6 Dx 100GbE QSFP56 2-port PCIe Ethernet Adapter

  • ThinkSystem Nvidia ConnectX-7 NDR200/HDR QSFP112 2-Port PCIe Gen5 x16 InfiniBand Adapter

  • ThinkSystem Nvidia ConnectX-7 10/25GbE SFP28 4-Port PCIe Ethernet Adapter(Generic)

20, 8, 18, 6, 16, 4, 19, 7

5

  • ThinkSystem Broadcom 5719 1GbE RJ45 4-Port PCIe Ethernet Adapter

  • ThinkSystem QLogic QLE2772 32Gb 2-Port PCIe Fibre Channel Adapter

  • ThinkSystem Mellanox ConnectX-6 Lx 10/25GbE SFP28 2-Port PCIe Ethernet Adapter

  • ThinkSystem QLogic QLE2872 64Gb 2-Port PCIe Fibre Channel Adapter(Generic FW)

  • ThinkSystem Emulex LPe38102 64Gb 2-port PCIe Fibre Channel Adapter

  • ThinkSystem Emulex LPe37102 32Gb 2-port PCIe Fibre Channel Adapter

  • ThinkSystem Intel E610-T4 10GBASE-T 4-port PCIe Ethernet Adapter(Generic FW)

20, 8, 14, 11, 18, 6, 19, 12, 13, 7, 9, 10, 16, 4, 15, 3, 17, 5

6

External HBA adapter

20, 8, 14, 11, 18, 6, 19, 12, 13, 7, 9, 10, 16, 4, 15, 3, 17, 5

7

OCP module

1, 2