Best practices for memory allocation and configuration include:
- Memory is often not the constraining resource; therefore, do not overcommit memory when sizing. Overcommitting memory increases the possibility of performance degradation if contention for memory resources, such as swapping and ballooning of memory, occurs. Overcommitted memory can also affect storage performance when swap files are created.
- Populate memory in units of 6 or 12 DIMMs per CPU to yield the highest performance. Dell PowerEdge servers using 4th generation AMD EPYC processors have 12 memory channels per CPU. Four internal memory controllers control the CPUs, each handling two memory channels. To ensure that your environment has the optimal memory configuration, use a balanced configuration, where each CPU supports a maximum of 12 DIMMs (or 24 DIMMs for a dual-CPU server). The most effective configuration is 16 DIMMs (8 per processor) with 4th generation AMD EPYC processors.