Even should not use mod.

IsEven.cs

void Main()
{
    var summary = BenchmarkRunner.Run<BenchmarkEven>();
}

[BenchmarkDotNet.Attributes.MemoryDiagnoser]
public class BenchmarkEven
{
    [Benchmark]
    [Arguments(42)]
    public bool IsEven(int i) => i % 2 == 0;

    [Benchmark]
    [Arguments(42)]
    public bool IsEven2(int i) => (i & 1) == 0;
}

Reseult.md

// * Summary *

BenchmarkDotNet=v0.13.1, OS=Windows 10.0.19043.1165 (21H1/May2021Update) AMD Ryzen 9 5900X, 1 CPU, 24 logical and 12 physical cores .NET SDK=5.0.400 [Host] : .NET 5.0.9 (5.0.921.35908), X64 RyuJIT

Method	i	Mean	Error	StdDev	Allocated
IsEven	42	0.1749 ns	0.0056 ns	0.0052 ns	-
IsEven2	42	0.0000 ns	0.0000 ns	0.0000 ns	-

from: https://devblogs.microsoft.com/dotnet/performance-improvements-in-net-6/

dotnet/runtime#45463. i % 2 == 0. The JIT can now transform that into code more like i & 1 == 0