When making a pattern with a lot of instances, performance can take a major hit when editing the part and any assemblies that contain it. The reason for this is that SolidWorks is recreating the seed or parent feature(s) i.e. (Cut-Extrude -> Through All, Fillet on 4 edges) that you are making the pattern from. Simply put, SolidWorks is calculating each feature for each pattern instance. So if your features take one second to rebuild and you make a pattern of them 10 times, this will result in 10 seconds of rebuild time for SolidWorks to calculate the pattern.
In this example, the seed features to pattern are a diamond shaped Cut-Extrude with Fillets on multiple edges. The pattern is 99 rows by columns (1881 copies) with the rebuild time on my computer calculating in at 215.98 seconds, approximately 3 minutes and 36 seconds, as shown by the Tools>Feature Statistics.
In order to improve rebuild time or increase performance, there is an options setting called Geometry Pattern located at the bottom of the pattern dialog box (see picture below). Geometry pattern simplifies the calculations that SolidWorks has to perform. Instead of recreating all of the patterned features at each instance, SolidWorks will simply ‘copy’ the geometry to pattern for each instance “as is”.
In this example the rebuild time was drastically reduced by using the Geometry Pattern option as shown by the Tools>Feature Statistics; this same pattern rebuilds in just under 4 seconds.
Depending on the geometry of your parts, you may want to try this option which can greatly speed up your SolidWorks rebuild time and enhance performance.