I/O Expansion Options - IBM x3755 M3 Product Manual

I/O expansion options

The server offers four PCI Express slots (one of them is reserved for the RAID controller) that are located
on a riser card. The slot form factors are:
Slot 1: PCIe 2.0 x16, full height, full length
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Slot 2: PCIe 2.0 x8, low profile, half length
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Slot 3: PCIe 2.0 x8 (x4 wired), low profile, half length
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Slot 4: PCIe 2.0 x8, low profile, half length (internal only, reserved for RAID controller)
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Figure 6 shows the location of the adapter slots on a riser card.
Figure 6. Adapter slots in the x3755 M3
IBM System x3755 M3 15