Hardware options installation 42
DIMM identification
To determine DIMM characteristics, use the label attached to the DIMM and the following illustration and
table.
Item Description Definition
1
Size —
2
Rank 1R = Single-rank
2R = Dual-rank
4R = Quad-rank
3
Data width x4 = 4-bit
x8 = 8-bit
4
Voltage rating L = Low voltage (1.35v)
U = Ultra low voltage (1.25v)
Blank or omitted = Standard
5
Memory speed 12800 = 1600-MT/s
10600 = 1333-MT/s
8500 = 1066-MT/s
6
DIMM type R = RDIMM (registered)
E = UDIMM (unbuffered with ECC)
L = LRDIMM (load reduced)
For the latest supported memory information, see the QuickSpecs on the HP website
(http://h18000.www1.hp.com/products/quickspecs/ProductBulletin.html). At the website, choose the
geographic region, and then locate the product by name or product category.
Memory configurations
To optimize server availability, the server supports the following AMP modes:
• Advanced ECC—provides up to 4-bit error correction and enhanced performance over Lockstep mode.
This mode is the default option for this server.
• Online spare memory—provides protection against failing or degraded DIMMs. Certain memory is
reserved as spare, and automatic failover to spare memory occurs when the system detects a DIMM that
