Dell OptiPlex 7020 Owner's Manual page 28

1. PCI Express x16 slot (wired as X4)
2. PCI slot
3. PCIe x1 slot
4. coin-cell battery
5. PCI Express x16 slot
6. intrusion switch connector
7. 4–pin CPU power connector
8. system fan connector
9. processor socket
10. heatsink fan connector
11. memory connectors ( SODIMM sockets)
12. front power-switch
13. 8–pin power connector
14. SATA connectors
15. HDD and optical drive power connector
16. SATA connectors
17. front panel USB connector
18. front panel audio connector
19. password reset jumper
20. internal USB 2.0 connector
21. RTCRST jumper connector
22. speaker connector
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