The HP BladeSystem PCI Expansion Blade provides PCI card expansion slots to an adjacent c-Class blade server. This blade expansion unit uses the c-Class midplane to pass standard PCI signals between adjacent enclosure bays, to allow a c-Class blade server to add off-the-shelf PCI-X or PCI-e cards. Customers would need one PCI Expansion Blade for each c-Class server blade needing PCI card expansion. Any PCI card from third-party manufacturers that works in HP ProLiant ML and HP ProLiant DL servers should work in this PCI Expansion Blade. HP does not offer any warranty or support for third-party PCI manufactured products. HP does joint market with selected PCI manufactures via the HP BladeSystem Solutions Builder Program.

Each PCI Expansion Blade can hold one or two PCI-X cards( 3.3V or universal); or one or two PCI-e cards(x1, x4, or x8). Installed PCI-X cards must use less than 25 watts per card. Installed PCIe cards must use less than 75 watts per PCIe slot, or a single PCIe card can use up to 150 watts, with a special power connector enabled on the PCI Expansion blade. Supports typical third-party (non-HP) PCI cards, such as SSL or XML accelerator cards, VOIP cards, special purpose telecommunications cards, and some graphic acceleration cards.