TX2550 M4 Upgrade and Maintenance Manual 293
Expansion cards and backup units
Figure 198: PCI slot overview on the rear - low performance
* When using an OCP module, the standard PCIe x16 slot is not usable.
PCI 
slot
Type CPU Type Length/Height Function
1 PCIe Gen 3 1 x8 (mechanical x8) max. 167 mm / FH
second RAID 
controller
2 PCIe Gen 3 1 x8 (mechanical x8) max. 167 mm / FH
preferred slot for RAID 
controller (system 
boot)
3 PCIe Gen 3 1 x8 (mechanical x8) max. 167 mm / FH
4PCIe Gen 31
x16 (mechanical 
x16)
max. 167 mm / FH
8PCIe Gen 32
x16 (mechanical 
x16)
max. 167 mm / FH
8* OCP 1 OCP connector
9PCIe Gen 32
x16 (mechanical 
x16)
max. 167 mm / FH