I/O Expansion Options - Lenovo System x3550 M5 Product Manual

I/O expansion options

The x3550 M5 server supports up to four PCIe slots: one on the system planar that is dedicated for an
internal RAID controller and up to three with different riser cards installed into two riser sockets on the
system planar (one riser socket supports the installation of one riser card). The slot form factors are listed:
Slot 1: PCIe 3.0 x16 or ML2; low profile, half-length (not present if the HDD Rear Kit is installed)
Slot 2: PCIe 3.0 x16 or PCIe 3.0 x8; low profile or full-height, half-length (PCIe 3.0 x16 slot requires
the second processor to be installed) (not present if the HDD Rear Kit is installed)
Slot 3: PCIe 3.0 x16 or PCIe 3.0 x8; low profile, half-length
Slot 4: PCIe 3.0 x8 (dedicated for an internal RAID controller)
The locations of the PCIe slots are shown in the following figure.
Figure 6. PCIe slot locations
Riser 1 supplies slot 1, and riser 2 supplies slots 2 and 3. All standard models have one riser card (Riser 1)
installed, which provides one low profile PCIe x16 Gen 3 slot (riser option part number 00KA061). You can
replace the first riser card or add a second riser card with the riser card options that are listed in the
following table (or configure these riser cards to be factory-integrated using special bid or CTO).
System x3550 M5 25