// setup initial vars
var myList = new List();
for (int x = 0; x < 10000000; x++)
    myList.Add(false);  

var containsAllFalse = false;
Stopwatch sw = new Stopwatch();

// start test
sw.Start();
containsAllFalse = !myList.Any(x => x);
sw.Stop();

// get result for Any
var timeAny = sw.ElapsedMilliseconds;

// reset variable state (just in case it affects anything)
containsAllFalse = false;   

// start test 2
sw.Restart();
containsAllFalse = myList.All(x => x == false);
sw.Stop();

// get result for All
var timeAll = sw.ElapsedMilliseconds;

// reset variable state (just in case it affects anything)
containsAllFalse = false;   

// start test 3
sw.Restart();
containsAllFalse = !myList.Exists(x => x == true);
sw.Stop();

// get result for All
var timeExists = sw.ElapsedMilliseconds;

// reset variable state (just in case it affects anything)
containsAllFalse = false;   

// start test 4
sw.Restart();   
containsAllFalse = !myList.Contains(true);          
sw.Stop();

// get result from Contains
var timeContains = sw.ElapsedMilliseconds;

// print results
var percentFaster = Math.Round((double)timeAny / timeContains, 2);
Console.WriteLine("Elapsed via Any = {0}ms", timeAny);
Console.WriteLine("Elapsed via All = {0}ms", timeAll);
Console.WriteLine("Elapsed via Exists = {0}ms", timeExists);
Console.WriteLine("Elapsed via Contains = {0}ms", timeContains);
Console.WriteLine("Contains is ~{0}x faster than Any!", percentFaster);