ForEachOnArrayWhereSelect Source ForEachOnArrayWhereSelect.cs Results: BenchmarkDotNet=v0.13.2, OS=Windows 11 (10.0.22621.819) Intel Core i7-8750H CPU 2.20GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores .NET SDK=7.0.100 [Host] : .NET 7.0.0 (7.0.22.51805), X64 RyuJIT AVX2 DefaultJob : .NET 7.0.0 (7.0.22.51805), X64 RyuJIT AVX2 Method Mean Error StdDev Allocated SysLinq 49.25 μs 0.138 μs 0.122 μs 104 B StructLinqWithDelegate 34.00 μs 0.185 μs 0.155 μs - StructLinqWithDelegateAsEnumerable 44.51 μs 0.240 μs 0.213 μs 104 B StructLinq 13.66 μs 0.063 μs 0.052 μs - StructLinqAsEnumerable 26.15 μs 0.270 μs 0.252 μs 104 B