System board connectors
See this section to identify the connectors on the system board.
Figure 7. System board connectors
Table 7.  System board connectors
1  Serial connector 15  External LCD diagnostics handset connector
2  VGA connector
16  Fan connectors
3  Two USB 3.1 
17  Processor and memory expansion tray power 
connector
4  XClarity Controllernetwork connector
18  Power backplane sideband connector
5  NMI button
19  Front VGA connector
6  TCM/TPM module
20  Power backplane power connector
7  PCIe riser connector (PCIe slot 1 to 3) 21  PCIe signal connector 1
8  OCP connector (PCIe slot 4) 22  On-board SATA connector
9  USB front panel module connector 23  PCIe riser connector (PCIe slot 5 to 6)
10  PCIe signal connector 2 24  PCIe slot 7 (x8)
11  UPI connectors
25  PCIe slot 8 (x8)
28 ThinkSystem SR850 V2 Maintenance Manual