User Manual

Hardware options installation 52
Hemisphere mode
The Intel® Xeon® E7 family and 7500 series processor architectures incorporate Hemisphere mode, a
high-performance interleaving technology. Hemisphere mode combines the tracking resources of both
memory controllers within each processor for a more aggressive cache line pipelining.
Hemisphere mode is enabled when processors in the system have identical DIMM populations behind both
of their memory controllers. Observe the following guidelines:
• Hemisphere mode is controlled via an RBSU option, enabling the user to select either automatic (default)
or disable.
• In automatic mode, the BIOS enables Hemisphere mode if the system memory configuration is
compatible with Hemisphere mode.
• Hemisphere mode should produce the best overall performance for a variety of applications. However,
Hemisphere mode can be disabled if it produces lower performance for a particular application.
• To enable each processor to enter Hemisphere mode, all memory controllers must be installed and
populated with equal memory capacities based on the DIMM installation guidelines (on page 49).
• Greater performance is obtained when all memory controllers are populated with either four or eight
dual- or quad-rank DIMMs.
• Mirrored Memory mode is not supported when Hemisphere mode is enabled.