Specifications

Chapter 2. Architecture and technical overview 71
2.8 PCI adapters
This section covers the different types and functionalities of the PCI cards supported by IBM
Power 770 and Power 780 systems.
2.8.1 PCIe Gen1 and Gen2
Peripheral Component Interconnect Express (PCIe) uses a serial interface and allows for
point-to-point interconnections between devices (using a directly wired interface between
these connection points). A single PCIe serial link is a dual-simplex connection that uses two
pairs of wires, one pair for transmit and one pair for receive, and can transmit only one bit per
cycle. These two pairs of wires are called a
lane. A PCIe link can consist of multiple lanes. In
such configurations, the connection is labeled as x1, x2, x8, x12, x16, or x32, where the
number is effectively the number of lanes.
Two generations of PCIe interface are supported in Power 770 and Power 780 models:
򐂰 Gen1: Capable of transmitting at the extremely high speed of 2.5 Gbps, which gives a
capacity of a peak bandwidth of 2 GBps simplex on an x8 interface
򐂰 Gen2: Double the speed of the Gen1 interface, which gives a capacity of a peak
bandwidth of 4 GBps simplex on an x8 interface
PCIe Gen1 slots support Gen1 adapter cards and also most of the Gen2 adapters. In this
case, where a Gen2 adapter is used in a Gen1 slot, the adapter will operate at PCIe Gen1
speed. PCIe Gen2 slots support both Gen1 and Gen2 adapters. In this case, where a Gen1
card is installed into a Gen2 slot, it will operate at PCIe Gen1 speed with a slight performance
enhancement. When a Gen2 adapter is installed into a Gen2 slot, it will operate at the full
PCIe Gen2 speed.
The IBM Power 770 and Power 780 CEC enclosure is equipped with six PCIe x8 Gen2 slots.
2.8.2 PCI-X adapters
IBM offers PCIe adapter options for the Power 770 and Power 780 CEC enclosure. If a
PCI-extended (PCI-X) adapter is required, a PCI-X DDR 12X I/O Drawer (#5796) can be
attached to the system by using a GX++ adapter loop. PCIe adapters use a different type
of slot than PCI and PCI-X adapters. If you attempt to force an adapter into the wrong type
of slot, you might damage the adapter or the slot. All adapters support Extended Error
Handling (EEH).
2.8.3 IBM i IOP adapters
IBM i IOP adapters are not supported with the Power 770 and Power 780, which has
these results:
򐂰 Existing PCI adapters that require an IOP are affected.
򐂰 Existing I/O devices are affected, such as certain tape libraries or optical drive libraries, or
any HVD SCSI device.
򐂰
Twinax displays or printers cannot be attached except through an OEM protocol converter.
Before adding or rearranging adapters, use the System Planning Tool to validate the new
adapter configuration. See the System Planning Tool website:
http://www.ibm.com/systems/support/tools/systemplanningtool/