IEquatable<T> Performance with List<T> and structs

IEquatableComparison.cs

using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;

int capacity = 10_000_000;
List<Vector3NoEquals> Vector3NoEquals = new(capacity);
List<Vector3WithEquals> Vector3GoodEquals = new(capacity);
List<Vector3WithIEquality> Vector3WithIEquality = new(capacity);

for (int i = 0; i < capacity; i++)
{
    Vector3NoEquals.Add(new Vector3NoEquals(i, i, i));
    Vector3GoodEquals.Add(new Vector3WithEquals(i, i, i));
    Vector3WithIEquality.Add(new Vector3WithIEquality(i, i, i));
}

var index1 = new Vector3NoEquals(capacity / 2, capacity / 2, capacity / 2);
var index2 = new Vector3WithEquals(capacity / 2, capacity / 2, capacity / 2);
var index3 = new Vector3WithIEquality(capacity / 2, capacity / 2, capacity / 2);

Console.WriteLine($"Results for {capacity.ToString("N")} iterations on a list.");
Stopwatch sw = Stopwatch.StartNew();
// -------------------
Vector3NoEquals.Contains(index1);
Console.WriteLine($"Vector 3 without equality override, Contains(miliseconds) {sw.ElapsedMilliseconds}");
sw.Restart();
// --
Vector3GoodEquals.Contains(index2);
Console.WriteLine($"Vector 3 with good equality override, Contains(miliseconds) {sw.ElapsedMilliseconds}");
sw.Restart();
// --
Vector3WithIEquality.Contains(index3);
Console.WriteLine($"Vector 3 with IEquality, Contains(miliseconds) {sw.ElapsedMilliseconds}");
sw.Restart();

struct Vector3WithIEquality : IEquatable<Vector3WithIEquality>
{
    public int x;
    public int y;
    public int z;

    public Vector3WithIEquality(int x, int y, int z)
    {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    public bool Equals(Vector3WithIEquality other)
    {
        return x == other.x && y == other.y && z == other.z;
    }

    //public override bool Equals(object obj) // Overridden from object
    //{
    //    if (!(obj is Vector3WithIEquality))
    //        return false;

    //    Vector3WithIEquality v3 = (Vector3WithIEquality)obj;

    //    return
    //        this.x == v3.x &&
    //        this.y == v3.y &&
    //        this.z == v3.z;
    //}

    public override int GetHashCode()
    {
        return this.x.GetHashCode() ^ this.y.GetHashCode() << 2 ^ this.z.GetHashCode() >> 2;
    }
}

struct Vector3NoEquals
{
    public int x;
    public int y;
    public int z;

    public Vector3NoEquals(int x, int y, int z)
    {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    public override int GetHashCode()
    {
        return this.x.GetHashCode() ^ this.y.GetHashCode() << 2 ^ this.z.GetHashCode() >> 2;
    }
}

struct Vector3WithEquals
{
    public int x;
    public int y;
    public int z;

    public Vector3WithEquals(int x, int y, int z)
    {
        this.x = x;
        this.y = y;
        this.z = z;
    }

    public override bool Equals(object obj) // Overridden from object
    {
        if (!(obj is Vector3WithEquals))
            return false;

        Vector3WithEquals v3 = (Vector3WithEquals)obj;

        return
            this.x == v3.x &&
            this.y == v3.y &&
            this.z == v3.z;
    }

    public override int GetHashCode()
    {
        return this.x.GetHashCode() ^ this.y.GetHashCode() << 2 ^ this.z.GetHashCode() >> 2;
    }
}