#Lets create some test data
$ItemCount = 10000
$Iterations = 10000
$ItemArray = [string[]]::new($ItemCount) #Pre-initialize your arrays with a length

#Now we fill the array with random data
$Randomizer = [Random]::new()
for ($I = 0; $I -lt $ItemCount; $I++) {
    $ItemArray[$I] = [GUID]::NewGuid().ToString()
}

#Now lets create another array. This array will be used to query the original to see if stuff exists in it.
#We will also make sure half the entries do not exist
$QueryArray = @(0)*$Iterations
for ($I = 0; $I -lt $Iterations/2; $I++) {
    $QueryArray[$I] = [GUID]::NewGuid().ToString()
}
for ($I = $Iterations/2; $I -lt $Iterations; $I++) {
    $QueryArray[$I] = $ItemArray[$Randomizer.Next(0,$ItemArray.Length)]
}

$UnsortedMetrics = Measure-Command {
    for ($I = 0; $I -lt $Iterations; $I++) {
        $null=$ItemArray.Contains($QueryArray[$I])
    }
}

#Now we sort it and try again with BinarySearch
[Array]::Sort($ItemArray)

$SortedMetrics = Measure-Command {
    for ($I = 0; $I -lt $Iterations; $I++) {
        $null=[Array]::BinarySearch($ItemArray, $QueryArray[$I])
    }
}