Home > Workload Solutions > Oracle > Best Practices > AMD-Based Oracle Best Practices on Dell PowerEdge R740 and PowerMax 2000 > CPU Best Practices > Day Three Best Practices > PowerEdge: DRAM Refresh delay and Opportunistic Self-Refresh
There are two BIOS settings, DRAM refresh Delay and Opportunistic Self-Refresh, that have the potential to improve performance. In this best practice we will explore changes to the DRAM refresh delay and Opportunistic Self-Refresh settings.
Category | Performance |
Product | PowerEdge R7525 |
Type of best practice | Performance Optimization |
Day and value | Day 3, Fine Tuning |
Overview of DRAM Refresh Delay
There are several settings in BIOS that enable optimizing system memory performance. The first one is called, DRAM Refresh Delay and is set to a Minimum setting as its default. This setting instructs the CPU memory controller to minimize the delay time, to ensure the memory controller runs the refresh command at regular intervals.
For this best practice, the DRAM Refresh Delay was changed from its default to Performance. Performance mode causes the CPU memory controller to delay running refresh commands, potentially improving performance for some workloads.
Overview of Opportunistic Self-Refresh
Another BIOS memory setting is the Opportunistic Self-Refresh. By default, this memory setting it is set to Disabled. The disabled setting instructs the Integrate Memory Controllers not to complete a self-refresh when idle. For this best practice, the Opportunistic Self-Refresh BIOS setting was changed from its default to Enabled.
When set to Enabled, the Integrated Memory Controllers may go into Self-Refresh when idled for a period of time.
Recommendation
Changing the DRAM Refresh settings from Delay to Performance and the Opportunistic Self-Refresh settings from Disabled Enabled showed no significant change in these performance metrics:
Slight improvements were observed in these performance metrics:
Analysis in overall server utilization and PowerMax IOPS show a slight increase in these metrics when compared to the prior test. Consider implementing these BIOS changes to optimize Memory performance. Although our performance tests showed only slight gains, the value of this best practice might add up over time.
Implementation Steps
Use the following steps to view/update the settings: DRAM refresh delay and Opportunistic refresh delay, that are included in the Memory settings section of the BIOS settings.
Additional Resources
Dell Support has BIOS settings for the AMD based servers like the PowerEdge R7525