Memory upgrade
Although for daily usage 2 to 4 GB of RAM may seem sufficient, when it comes to CAE, all that memory space is soon swallowed up. As I will be using CFD quite a lot, lets see what are the recommended hardware requirements to run such CAE clients and how much will I gain by upgrading to 8 GB of DDR2-800 —which isn’t much by today’s standards.
| Hardware Requirements | |
| Processor | 2.4 GHz with at least 4 cores per GPU. |
| Memory | 2 GB of memory per core. |
| Memory Requirements for Meshing | |
| Surface meshing | 0.5 GB per million surface triangles. |
| Volume meshing (polyhedral) | ~1 GB per million cells. |
| Volume meshing (trimmed cells) | ~0.5 GB per million cells. |
| Memory Requirements for Solving in Serial with a Two-Equation Turbulence Model | |
| Polyhedral | |
| Segregated | 1 GB per million cells. |
| Coupled Explicit | 2 GB per million cells. |
| Coupled Implicit | 4 GB per million cells. |
| Trimmed cells | |
| Segregated | 0.5 GB per million cells. |
| Coupled Explicit | 1 GB per million cells. |
| Coupled Implicit | 2 GB per million cells. |
According to the previous chart now I should be able to solve cases with the double of cells, up to 2 million cells for the worst case scenario —without taking into consideration that the OS, all the applications, and the GUIs also require some of that RAM—. Although by upgrading memory capacity only I will not boost performance significantly, for me, adding 2 more memory modules is enough to extend my old QuadCore’s lifetime a few additional years. Nonetheless, shall I buy a new computer, I will follow the advice of CapSizer [2]:
The two characteristics of memory that do make a huge difference to CFD speed are the actual memory clock speed (get the fastest supported by the chipset) and the number of memory channels. Inexpensive single socket systems (AMD FX, Intel i5) use two parallel memory channels (typically, but not always, 4 slots in total). By contrast the current Intel i7 uses four (either 4 or 8 slots in total). When you measure CFD performance, you find that this is what really makes the difference.
References
[1] Installation Guide STAR-CCM+ Version 8.06. 2013.
[2] CFD Online. 2013. Advice on the technical requirements for a new Fluent Workstation. [online] Available at: http://www.cfd-online.com/Forums/hardware/113263-advice-technical-requirements-new-fluent-workstation.html#2 [Accessed: 3 Dec 2013].