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Xserve G5 takes the
ultrahigh-bandwidth system architecture of the Power Mac G5 to the next
level, giving you the power and throughput you need for demanding
Internet applications, robust network infrastructure and high
performance computational clustering environments.
Xserve G5 features the industry’s fastest frontside bus to keep data
moving in and out of the processor, and a superefficient point-to-point
system controller allows data to move directly between all subsystems,
without affecting the processor. Bandwidth is further optimized by a
400MHz, 128-bit memory bus and a low-latency HyperTransport interface
that connects the PCI-X controller and the I/O subsystems to the system
controller.
Dual onboard Gigabit Ethernet on an independent PCI bus eliminates
network contentions with the I/O subsystems for thoughput of up to 100
Mbps per port. With the multihoming feature of Mac OS X Server, Xserve
G5 lets you serve more client systems, provide redundant links or
support an isolated management network. |
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 Frontside
Bus of 1.0 GHz
Designed to harness the power of the G5 processor, a 1.0GHz, 64-bit
bidirectional Double Data Rate (DDR) frontside bus maximizes throughput
between the processor and the system controller. The Xserve G5 features
two high-speed unidirectional 32-bit data paths — one flowing
continuously into the processor and one flowing from the processor.
This lets data move in opposite directions simultaneously, with no
other demands on the data stream and no wait time while the processor
and system controller compete for use of the bus. What’s more, the data
streams integrate clock signals along with the data, allowing the
frontside bus to work at speeds of up to 1GHz for 8GB per second of
aggregate bandwidth.
 Dual Independent Frontside Buses
Naturally, dual processor systems get an even bigger performance boost.
Each PowerPC G5 processor has its own dedicated bidirectional interface
to the system controller. That’s 16GB per second of total bandwidth on
dual 2GHz systems — more than twice the 6.4GBps maximum bandwidth of
Xeon-based systems using the latest PC architecture. In addition to
providing fast access to main memory, this high-performance frontside
bus architecture enables each PowerPC G5 processor to discover and
access data in the other processor’s L1 and L2 caches for ultrafast
performance.
 Advanced PowerPC G5 System Controller
Central to the overall performance of the G5 processor is a new system
controller. Built using the same state-of-the-art IBM process
technology as the G5 processor itself, this revolutionary chip’s
point-to-point architecture provides each primary subsystem with
dedicated throughput to main memory, neatly avoiding time-consuming
contention for bandwidth (unlike subsystems that share a bus and are
compelled to constantly negotiate for access and bandwidth across a
common data path).
 400MHz Error Correction Memory
The Xserve G5 memory controller supports fast 400MHz, 128-bit DDR
SDRAM, and enables main memory to address two banks of SDRAM at a time,
reading and writing on both the rising and falling edge of each clock
cycle. This effectively doubles the bandwidth, enabling the Power Mac
G5 to reach a maximum memory throughput of up to 6.4GB per second. In
addition, direct memory access (DMA) works with the point-to-point
system controller to give each subsystem — such as PCI cards and I/O —
its own 6.4GBps interface to main memory, without siphoning power from
your processors.
Xserve G5 comes standard with 512MB or 1GB of DDR SDRAM, scalable to
8GB. That’s enough to process huge data sets and rich media files
within system RAM, without the delay of having to access the disk
drive. Xserve G5 uses Error Correction Code (ECC) logic to protect the
system from corrupt data and transmission errors. Each DIMM has an
extra memory module that stores checksum data for every transaction.
The system controller uses this ECC data to identify single-bit errors
and corrects them on the fly, preventing unplanned system shutdowns. In
the rare event of multiple-bit errors, the system controller detects
the error and triggers a system notification to prevent bad data from
corrupting further operations. You can set the Server Monitor software
to alert you if error rates exceed a particular threshold. |
 133MHz PCI-X Expansion
Xserve G5 features the latest 133MHz PCI-X expansion protocol with
throughput of 1GBps. PCI-X operates more efficiently than PCI,
resulting in more usable bandwidth at any clock frequency — ideal for
connecting to high-performance networking, storage, and backup devices
using optional SCSI and Fibre Channel cards. Two open 64-bit PCI-X
slots on independent buses allow you to add one card running at 133MHz
or two cards running at 100MHz.
 Dual Onboard Gigabit Ethernet
Apple strengthens the Ethernet implementation on the Xserve G5 by
adding a high-performance ASIC to the main logic board. This advanced
microprocessor includes two independent 10/100/1000BASE-T Ethernet
interfaces, each with its own interrupt, on a dedicated 64-bit, 133MHz
PCI-X bus. The Gigabit Ethernet chip uses hardware-generated TCP, IP,
and UDP checksum to detect packet corruption and transmission errors.
802.1q VLAN (Virtual LAN) tags let you group systems on different
physical LANs and provide discrete services to them — as if they were
on a single, physical LAN. What’s more, A 64KB buffer supports jumbo
frames, or packets up to 9KB, to reduce system overhead and increase
throughput of all network activities. In addition to serving the needs
of network clients, Dual Gigabit Ethernet also enables the high-speed
network interconnect required by many computational cluster deployments.
 Optical Drive
For software installation and recovery, a slot-loading 24x-speed CD-ROM
drive comes standard on server configurations. If you need to read DVD
data and back up data on CDs, you may choose a Combo drive option
(DVD-ROM/CD-RW).
 High-performance I/O
The Xserve G5 architecture uses the HyperTransport protocol to connect
the I/O controller to the system controller. The Serial ATA controller,
optical drive, and FireWire, USB 2.0, and serial ports are all
integrated through a bidirectional 800MHz HyperTransport interconnects
for a maximum throughput of 1.6GBps.
 Serial ATA Storage
Xserve G5 features sophisticated 150Mbps SATA drive controllers, each
with a dedicated SATA bus to a single Apple Drive Module, which
provides multithreaded system operation. Multithreading enables the
system to send commands to multiple drives at once for the fastest
possible throughput. An independent drive architecture also isolates
the drives electrically, preventing a single drive failure from causing
unavailability or performance degradation of the surviving drives — a
common problem with multidrive SCSI implementations.
 FireWire, Serial and USB Ports
Two FireWire 800 ports on the back panel and one FireWire 400 port on
the front panel connect to high-bandwidth FireWire (IEEE 1394) devices.
In addition, you can use TCP/IP over FireWire to network small
clusters, and clone configurations easily using FireWire Target Disk
Mode. An industry-standard 9-pin serial port lets you access the system
through a serial console session. Two USB 2.0 ports let you connect
Xserve G5 to industry-standard peripheral devices. |
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