Xor combination of two Guids.

Xor.cs

public static Guid Xor(Guid a, Guid b)
{
    var ad = new DecomposedGuid(a);
    var bd = new DecomposedGuid(b);

    ad.Hi ^= bd.Hi;
    ad.Lo ^= bd.Lo;

    return ad.Value;
}

[StructLayout(LayoutKind.Explicit)]
private struct DecomposedGuid
{
    [FieldOffset(00)] public Guid Value;
    [FieldOffset(00)] public long Hi;
    [FieldOffset(08)] public long Lo;
    public DecomposedGuid(Guid value) : this() => Value = value;
}

Ok, the differences appear to be system related, something else is running on my system, after reboot it looks like:

BenchmarkDotNet=v0.11.2, OS=Windows 10.0.17134.376 (1803/April2018Update/Redstone4)
Intel Xeon CPU E5-1620 0 3.60GHz, 1 CPU, 8 logical and 4 physical cores
.NET Core SDK=2.2.100-preview3-009430
  [Host]     : .NET Core 2.1.5 (CoreCLR 4.6.26919.02, CoreFX 4.6.26919.02), 64bit RyuJIT
  DefaultJob : .NET Core 2.1.5 (CoreCLR 4.6.26919.02, CoreFX 4.6.26919.02), 64bit RyuJIT

Method	Mean	Error	StdDev
XorPointer	10.47 ns	0.3285 ns	0.3226 ns
XorUnsafe	14.37 ns	0.1059 ns	0.0939 ns
XorSafe	11.21 ns	0.1026 ns	0.0801 ns

Yeah, that's what I expected 😄👍