Maximizing Memory Performance for Ansys Simulations

Ansys High-Performance Computing (HPC) | Tips & Tricks

Maximizing Memory Performance, or RAM, is important when you’re configuring computers for high-performance computing (HPC). Computer performance is affected not only by the amount of RAM but also by the amount of bandwidth, or transfer speed, between the processor and the memory.

The bandwidth is affected by the speed of the memory stick, but the way memory sticks are configured on the motherboard is even more important.

Accessing Multiple Memory Sticks

CPUs can access information on multiple memory sticks in parallel through use of memory channels. Modern CPUs can access between 1 and 8 memory channels simultaneously (model specific). Not only does this capability affect the machine’s performance.

Additionally, we have found that many computers are not configured to make use of all their memory channels.  In effect, hampering overall performance, and grade of simulation.


Example Memory Channel Diagram in Motherboard Manual

One of the main reasons people witness disappointing performance gains when adding more cores to their simulations is not due to the inefficiency of the solver code.  Instead, due to a combination of decreasing core frequency (turbo speed) and subdivision of out-of-core resources.  This is particularly relevant for PC memory bandwidth.

Maximizing Memory Performance for Ansys Simulations

In this paper, a SimuTech Group HPC Expert shares our recent test.  Specifically, how memory channels can impact your simulation performance.


Topic areas include:

  • CPU data starvation, and how to overcome it
  • Testing of memory bandwidth via RAM configuration changes.
  • Demonstrating that memory bandwidth can impact solve time by as much as 225% on a simple 8 core test
  • Why buying one memory stick and planning to get more later is not the best plan
  • CPU scaling in constant vs. increasing memory bandwidth scenarios: our test results
  • Scanning the market – what to look for in buying a new computer
  • An illustrated example using a CFX pump
  • Configuring a new or existing system’s memory for maximum performance
  • Including, the windows command to check your memory layout

Memory Bandwidth Impact on Solve Time | Infographic


Additional Ansys Software Tips & Tricks Resources


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