Projects can vary in size from small to large. On occasion, the larger projects may demand larger models in order to capture the full scope of the project. With increasingly complex models and intricate parts with many features it will invariably have an impact on your computer performance. It is worth noting that there are simple tricks you can use to improve performance for large assemblies.
Change the display to Shaded or Wireframe
This is one of the simplest and easiest methods, simply drop down the view bar options and select either shaded or wireframe. This can give a boost to performance.
Set it to lightweight
When a component is set to fully resolved, all of the model data is loaded into memory. When it is set to lightweight, only some of the model data is loaded into memory, the rest is loaded as required. This applies to both parts and assemblies. Consider the following gearbox assembly:
Right click on a component, in this case a part was chosen, and select component properties.
The component property box will appear where you can navigate to Suppression State and select Lightweight
In doing so the components will be set to lightweight, furthermore as a visual cue, SolidWorks modifies the part icon to include a feather to indicate that it is lightweight.
Activate Large Assembly Mode
Large assembly mode is an optimized set of system settings that will improve performance for larger assemblies. Upon opening an assembly a dialogue box will open when SolidWorks determines that the component is a large assembly (i.e. a threshold has been reached). You may choose to accept large assembly mode by accepting the dialogue box. Or you may manually turn on large assembly mode by going to tools > Large assembly mode