Tested on my machine and got following results: C# with dotnet run -c Release : RESULT Optimus route : 0 7 2 3 4 12 6 8 1 11 10 5 9 0 Distance : 7293 Elapse Time : 18.1769783 s C# with csc (unoptimized): RESULT Optimus route : 0 7 2 3 4 12 6 8 1 11 10 5 9 0 Distance : 7293 Elapse Time : 22.14066 s

You're testing C# against the old .NET Framework 4.x with an unoptimized build. (csc produces unoptimized build by default).