How Unity Developers Can Eliminate GC Allocations Using Structs and Span

Unity games often suffer from unexpected frame stutters not due to GPU load but because of frequent Garbage Collector cycles triggered by hidden heap allocations. The root cause is typically the use of class-based temporary data structures, where each 'new' instance creates a separate managed heap allocation that the GC must later reclaim. A common example is creating class instances inside an Update loop — even 10 such allocations per frame can accumulate into disruptive GC stalls over time. The recommended solution is to replace these class-based structures with C# structs, which are value types allocated on the stack rather than the heap. Combining structs with Span for transient data can virtually eliminate GC.Alloc calls from high-frequency game logic, resulting in smoother frame rates and a more efficient codebase.