It's not just column-based access. Formatting your data into a struct of arrays exposes opportunites to pack your data more efficiently and greatly reduce your

It's not just column-based access. Formatting your data into a struct of arrays exposes opportunites to pack your data more efficiently and greatly reduce your application's memory usage. Boolean struct fields can become bitsets. Nullable struct fields can become sparse (or dense) maps. Pointer/reference struct fields can become arrays of smaller-width integers that index into a pool. And so on. When everything runs on CPUs that frequently stall on memory accesses, the impact of these sorts of changes cannot be understated - the latency difference between L3 cache and RAM can be on the order of ~10x.