Cray XT4™ Compute Blade
Cray XT4™ Compute Blade
To solve the most challenging scientific and engineering problems, users
need scalable computational power. The Cray XT4 blade was designed from
the ground up to address a scalable MPI workload. Particularly well suited
to problems which require a high-performance interconnect, the Cray XT4 is
designed to deliver faster solutions, and meet the demanding requirements
of high performance computing (HPC) applications.
enables a 6.4 GB/s direct connection between the compute
node and the Cray SeaStar2+ interconnect, removing the PCI
bottleneck inherent in commodity networks.
Each Cray XT4 node can be configured with 1 to 8 GB ECC DDR2
memory. Memory on compute nodes is unbuffered. This feature,
Cray XT4 Compute Blade
combined with the AMD Opteron’s integrated memory controller
provides applications with the lowest possible memory latency.
Scalable Interconnect
The Cray XT4 blade incorporates a high-bandwidth, low-latency
interconnect composed of Cray SeaStar2+ chips and high-speed
links based on HyperTransport and proprietary protocols. The
interconnect directly connects all compute nodes in a 3D torus
topology, eliminating the cost and complexity of external switches.
This improves reliability and allows the Cray XT4 system to
economically scale to tens of thousands of nodes. As the backbone
of the Cray XT4 system, the interconnect carries all message
9.6 GB/sec
passing traffic as well as all I/O traffic to the global file system.
associated with clusters of large SMPs. It also ensures that performance is
9.6 GB/se
9.6 GB/sec
Scalable Compute Nodes
Each Cray XT4 blade includes four compute nodes for high scalability in a
small footprint. Each compute node is composed of a single AMD Opteron™
processor (dual or quad core), each coupled with its own memory and
dedicated Cray SeaStar2+™ communication ASIC. This design eliminates
the scheduling complexities and asymmetric performance problems
9.6 GB/se
uniform across distributed memory processes – an absolute requirement for
scalable algorithms. Each compute node is designed to efficiently run up to
four MPI tasks, or alternately can be programmed to run OpenMP within a
compute node and MPI between nodes.
AMD Opteron
The AMD processor’s on-chip and highly associative data cache supports
aggressive out-of-order execution. The integrated memory controller
eliminates the need for a separate Northbridge memory chip, and provides
a high-bandwidth path to local memory – 12.8 GB/sec per single-socket
compute node. This design brings a significant performance advantage to
algorithms that stress local memory bandwidth. HyperTransport™ technology
Upgradeable and Flexible
Previous generation Cray XT3 systems can be upgraded to
accept the Cray XT4 compute blade. The Linux environment fully
supports mixing blade types between system cabinets or even within
a single cabinet providing customers with a variety of cost-effective
upgrade options.
Cray XT4 Specifications
64-bit AMD Opteron series 1000 processors; up to 96 per cabinet
64k L1 instruction cache, 64k L1 data cache, 512KB L2 cache per processor, 2MB unified L3 cache
3.5 Teraflops per cabinet
Main Memory
1-8 GB Unbuffered ECC DDR2 SDRAM per AMD Opteron
Memory Bandwidth
10.6 to 12.8 GB/sec per AMD Opteron
External I/O Interface
1 Cray SeaStar2+ routing and communications ASIC per Opteron processor
6 switch ports per Cray SeaStar2+ chip, 9.6 GB/s each (57.6 GB/s switching capacity per Cray SeaStar2+ Chip)
3-dimensional torus interconnect
Gigabit Ethernet
10 Gigabit Ethernet
Fibre Channel (FC)
Infiniband (future)
Disk Storage
Full line of FC-attached disk arrays with support for FC and SATA disk drives
File System
Lustre file system
Cray System Management Workstation (SMW)
System Administration
Graphical and command line system administration
Single-system view for system administration
PBS Pro job management system
System software rollback capability
Reliability Features
Cray RAS and Management Subsystem (CRMS) with independent 100 Mb/s
management fabric between all system blades and cabinet-level controllers.
More than 50 measurement points monitored per Cray XT4 system blade.
Full ECC memory protection from memory to system registers
Full ECC protection in the Cray SeaStar2+ chip
Redundant power supplies
Redundant voltage regulator modules (VRMs)
Redundant paths to all system RAID
Variable-speed blowers with integrated pressure and temperature sensors
Simple, micro-kernel-based software design
Reliability Features
CRMS system monitors operation of all operating system kernels
Operating System
Linux environment--Components include SUSE Linux™, Cray Catamount Microkernel, CRMS and SMW software
Message Passing Libraries
Fortran 77, 90, 95; C/C++, UPC
Lustre file system object storage target failover; Lustre metadata server failover
Software failover for critical system services including system database, system logger, and batch subsystems
15-24.6 kW (15.3-24.85 kVA) per cabinet, depending on configuration.
Circuit requirements (Cray XT5 high-density cabinet): 80 AMP at 400/480 VAC (3 phase & ground),
63 AMP at 400 VAC (3 phase, neutral, & ground)
Cooling Requirement
Air cooled, air flow: 3000 cfm (1.41 m3/s); intake: bottom; exhaust: top
Dimensions (Cabinet)
H 80.50 in. (2045 mm) x W 22.50 in. (572 mm) x D 56.75 in. (1441 mm)
Weight (Maximum)
1529 lbs per cabinet (694 kg)
Acoustical Noise Level
75 dba at 3.3 ft (1.0 m)
Regulatory Compliance
UL 60950-1, CAN/CSA - C 22.2 No. 60950-1, CB Scheme Investigation to IEC/EN 60950-1, RoHS, WEEE
FCC Class A, DOC Class A, VCCI Class, CISPR 22, EN 50022 Class A, AS/NZS 3548,
EN 50082-1, EN 61000-3-2, EN 61000-3-3, Statskontoret 26.2 Category 1
Technical specifications on this page are subject to change without notice.
© 2007 Cray Inc. All rights reserved. Specifications subject to change without notice. Cray is a registered trademark, and the Cray logo, Cray XT4, and Cray SeaStar2+ are
trademarks of Cray Inc. All other trademarks mentioned herein are the properties of their respective owners.
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