Chapter 2. Architecture and technical overview
15
Table 2-1 Theoretical throughput rates
2.4 Internal I/O subsystem
The internal I/O subsystem resides on the system board, and the flexible service processor
(FSP) is packaged on a separate service processor card. The system board contains the
Enterprise hub and the PCI-X host bridge chips to connect to the integrated I/O packaged on
the system board. Two ports of the Enterprise hub chip are used for the integrated I/O, and
the remaining two ports are routed to external connectors.
The system board provides six PCI-X slots and several integrated PCI devices that interface
the two PCI-X-to-PCI-X bridges to the primary PCI-X buses on the PCI-X host bridge chip.
PCI-X slots 1, 2, and 3 can accept short PCI-X or PCI cards only. The remaining three PCI-X
slots are full length cards. The dual 1 Gb Ethernet controller is integrated on the system
board.
2.4.1 PCI-X slots and adapters
PCI-X, where the X stands for extended, is an enhanced PCI bus, delivering a bandwidth of
up to 2 GBps, running a 64-bit bus at 266 MHz. PCI-X is backward compatible, so the
IntelliStation POWER 285 system can support existing 3.3 volt PCI adapters.
The slots have the following attributes:
Three hot-swap 133 MHz 64-bit PCI-X slots
Two hot-swap 66 MHz 32-bit PCI-X slots
One hot-swap DDR 266 MHz 64-bit PCI-X slot
The PCI-X slots in the IntelliStation POWER 285 system support hot-plug and extended error
handling (EEH). In the unlikely event of a problem, EEH-enabled adapters respond to a
special data packet generated from the affected PCI-X slot hardware by calling system
firmware, which will examine the affected bus, allow the device driver to reset it, and continue
without a system reboot.
The DDR PCI-X slot provides a high-bandwidth slot for future I/O-intensive adapters.
64-bit and 32-bit adapters
IBM offers 64-bit adapter options for the IntelliStation POWER 285 system, as well as 32-bit
adapters. Higher-speed adapters use 64-bit slots because they can transfer 64 bits of data for
each data transfer phase. Generally, 32-bit adapters can function in 64-bit PCI-X slots;
however, some 64-bit adapters cannot be used in 32-bit slots. For a full list of the adapters
that are supported on the IntelliStation POWER 285 system, and for important information
regarding adapter placement, see the IBM Systems Hardware Information Center,
available at this Web site:
http://publib.boulder.ibm.com/infocenter/eserver/v1r3s/index.jsp?lang=en
Processor speed
(GHz)
Processor Type
Cores
Memory
(GB/s)
L2 to L3
(GB/s)
GX+
(GB/s)
1.9
1-core
21.1
30.4
5.1
1.9
2-core
21.1
30.4
5.1
2.1
1-core
21.1
33.6
5.6
2.1
2-core
21.1
33.6
5.6
