Lenovo ThinkSystem SR250 Product Manual page 6

The following figure shows the locations of key components inside the SR250 server.
Figure 6. Internal view of the SR250
The SR250 server includes the following internal components:
One processor
Four DIMM slots
Up to three PCIe 3.0 slots:
Slot 1: PCIe 3.0 x8 (not present if the Slot 2 is PCIe x16)
Slot 2: PCIe 3.0 x8 or x16
Slot 4: PCIe 3.0 x4 (only supports a controller for internal storage)
Eight onboard SATA ports:
One Mini-SAS HD connector (4x SATA x1 ports)
Four SATA connectors (each connector provides the SATA x1 port)
One TCM/TPM connector (supports Nationz TPM available in PRC only)
Drive backplanes:
4x LFF SATA simple-swap bracket; or
4x LFF SAS/SATA hot-swap; or
8x SFF SAS/SATA hot-swap; or
8x SFF SAS/SATA and 2x SFF AnyBay hot-swap
Four non-hot-swap system fans
One M.2 connector
Lenovo ThinkSystem SR250 Server 6