How To
Summary
This is a brief guide on setting up and optimizing memory performance on your IBM Power E1080 machine. For the best possible performance, it is generally recommended that memory be installed evenly across all system node drawers and all processor sockets in the system. Balancing memory across the installed system planar cards enables memory access in a consistent manner and typically results in better performance for your configuration. Though maximum memory bandwidth is achieved by filling all the memory slots, plans for future memory additions should be considered when deciding which memory feature size to use at the time of initial system order.
Steps
• For each processor socket a minimum of 8 of the 16 DDIMMs (differential dual in-line memory modules) are populated
• In a node, a minimum of 32 of 64 for the DDIMMs are populated
• In a 4-Node system, a minimum of 128 of the 256 DDIMMs are populated
• Meet minimum memory allowed (each processor socket a minimum of 8 of the 16
DDIMMs are populated)
• All DDIMMs under each processor have to be same capacity
• Feature upgrades will be offered in increments of 4 DDIMM’s, all of which have the
same capacity.
• The only valid number of DDIMM’s plugged into sites connected to a given processor
module is 8 or 12 or 16.
• System performance improves as the amount of memory is spread across more DDIMM
slots.
For example, if 1TB is needed in a Node, it is better to have 64 x 32GB DDIMMs than
to have 32 x 64GB DDIMMs.
• Plugging DDIMMs that are all the same size will provide the highest performance
• System performance improves as more quads match each other
• System performance improves as more processor DDIMMs match each other
• System performance improves on a multi drawer system if memory capacity between
drawers are balanced.
Document Location
Worldwide
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Document Information
Modified date:
17 September 2024
UID
ibm17155063