Dell OptiPlex 7090 Setup And Specifications page 12

Discrete system board
1. M.2 WLAN connector
2. M.2 SSD PCIe connector
3. Coin-cell battery
4. M.2 SSD PCIe connector
5. Riser card connector
6. Processor socket
7. Memory slots
8. Intrusion switch
12 Views of OptiPlex 7090 Tower