Technologies in HP ProLiant G7 c-Class server blades with AMD Opteron™ processors, 3rd Edition

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Memory technologies
In AMD Opteron 6200 Series architecture, the design integrates the memory controller into the processor chip to
optimize memory performance and bandwidth per CPU. The memory controller reduces latency inherent in front
side bus architectures by eliminating the bus contention between memory and I/O cycles.
Memory bandwidth increases as you add processors to a configuration. One reason we chose to use AMD
Opteron 6200 Series processors in ProLiant G7 c-Class server blades was to use HP DDR3 DIMMs for energy
efficiency, high performance, and improved signal quality. We designed specific BIOS and RBSU functions to
manage memory configurations, so you can optimize configurations for maximum performance while reducing
power consumption and cooling requirements. These management options also include memory protection and
latency reduction.
The increased reliability of DDR3 on-DIMM thermal sensors allowed us to incorporate DIMM thermal data into the
advanced algorithms controlling thermal and power states within the server.
Unbuffered and registered DIMMs
ProLiant G7 server blades with AMD Opteron processors support Registered DDR3 DIMMs (RDIMMs). Depending
on memory size, rank, and configuration, RDIMMs support data rates of 1600, 1333, 1066, or 800 MT/s.
The BL465c G7 server blade with AMD Opteron processors supports Unbuffered DDR3 DIMMs (UDIMMs). UDIMM
configurations support two UDIMMs per memory channel. Depending on memory size, rank, and configuration,
UDIMMs support data rates of 1333, 1066, or 800 MT/s.
You cannot mix RDIMM and UDIMM memory within a single server. Both UDIMMs and RDIMMs support error
correcting code (ECC).
If you require large memory footprints, you can install two 32 GB RDIMMs per channel for a total of 512 GB for the
BL465c G7 and 1 TB for the BL685c G7. For smaller memory configurations, you should spread memory as evenly
as possible across the memory channels on a given processor and as evenly as possible across processors in a
given system.
You can take advantage of the HP low voltage (LV) DDR3 memory option. LV memory operates at 1.35-1.5 V with
no reduction in performance in some configurations and with reduced cooling requirements. If you mix LV and
standard voltage DDR3 DIMMs in a processor memory bank, all DIMMs will run at the higher voltage.
See the QuickSpecs to identify exactly what memory each server blade supports. For detailed memory configuration
guidelines, use the Online DDR3 Memory Configuration Tool available on the HP website at
www.hp.com/go/ddr3memory-configurator.
Memory interleaving
Memory interleaving on the AMD Opteron 6200 Series processors can occur between the processor memory
banks, between memory channels, and between processor nodes in a multi-processor system. ProLiant G7 c-Class
server blades with AMD Opteron 6200 Series processors support all three memory interleaving technologies. These
technologies are independent of each other and can operate simultaneously.
Memory bank interleaving
When you use memory bank interleaving, data goes alternately to memory banks through the common memory
channel connecting the DIMM banks and the integrated memory controller. Memory bank interleaving increases the
probability that more DIMMs will remain in an active state (requiring more power) because the memory controller
alternates between memory banks and between DIMMs.
Memory bank interleaving is automatically enabled on a processor node under the following conditions:
• Two single-rank DIMMs per channel result in two-way bank interleaving.