Home > Workload Solutions > SQL Server > Best Practices > AMD-Based SQL Server Best Practices on Dell PowerEdge R740 and PowerMax 2000 > CPU Best Practices > PowerEdge: DRAM Refresh and Opportunistic Self-Refresh
There are two BIOS settings that have potential to improve performance the DRAM refresh delay and Opportunistic Self-Refresh settings. In this best practice we will explore changes to each of these 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 by default is set to Minimum. The minimum 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 setting to Performance. When in Performance mode, the CPU memory controller will delay running the refresh commands, potentially improving performance for some workloads.
Overview of Opportunistic Self-Refresh
Opportunistic Self-Refresh is a BIOS memory setting with a default Disabled setting. 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 DRAM Refresh Delay to Performance and Opportunistic Self-Refresh to Enabled showed slight improvements in these performance metrics:
No significant performance metrics were observed with these performance metrics:
Overall, there was a slight increase in all performance metrics except, for Server CPU utilization. While the degree of performance improvement was slight overtime these BIOS settings can be valuable. Thus, changing the DRAM Refresh Delay and Opportunistic Self-Refresh are recommended as Day 3 activities for fine tuning your SQL Server system.
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