User guide

Hardware options installation 47
• Advanced ECC—provides the greatest memory capacity for a given DIMM size, while providing up
to 4-bit error correction. This mode is the default option for this server.
• Mirrored Memory—provides maximum protection against failed DIMMs. Uncorrectable errors in one
channel are corrected by the mirror channel.
• Lockstep—provides enhanced protection while making all installed memory available to the
operating system. The server can continue to function if a single- or mulit-bit memory failure within a
single DRAM device occurs.
Advanced Memory Protection options are configured in RBSU. If the requested AMP mode is not
supported by the installed DIMM configuration, the server boots in Advanced ECC mode. For more
information, see "HP ROM-Based Setup Utility (on page 92)."
For the latest memory configuration information, see the QuickSpecs on the HP website
(http://www.hp.com
).
RDIMM maximum memory configurations
The following table lists the maximum memory configurations possible with 16-GB RDIMMs.
Rank Single-processor Dual-processor
Single-rank 36 GB 72 GB
Dual-rank 72 GB 144 GB
Quad-rank 96 GB 192 GB
UDIMM maximum memory configurations
When using 2-GB single- or dual-rank UDIMMs, the server supports a maximum of 24 GB with one
processor and 48 GB with two processors.
Low voltage DIMMs
Low Voltage DDR3 DIMMs operate at a lower voltage (1.35V) than standard voltage DDR3 DIMMs
(1.5V), and therefore consume less power. However, LVDIMMs are configured to operated at standard
voltage levels (1.5V) under the following conditions:
• If LVDIMMs are mixed with standard DDR3 DIMMs on the same server, the LVDIMMs operate at
1.5V.
• If there are two dual-rank LVDIMMs per channel on any populated memory channel in the system
running at 1333 MHz, the LVDIMMs operate at 1.5V.
This setting preserves maximum memory subsystem performance. To have DIMMs operate at 1.35V,
configure the Maximum Memory Bus Frequency option in the ROM-Based Setup Utility to 1066
MHz.
• If there is one quad-rank LVDIMM per channel on any populated memory channel in the system
running at 1066 MHz, the LVDIMMs operate at 1.5V.
This setting preserves maximum memory subsystem performance. To have DIMMs operate at 1.35V,
configure the Maximum Memory Bus Frequency option in the ROM-Based Setup Utility to 800 MHz.
LVDIMMs are only supported for use with the Intel® Xeon® 5600 series of processors.