PHP script used for simple speed testing of different PHP versions. It generates (large) random numbers and checks if they are prime or not.

phpspeed.php

<?php

// Save the time when the script started running.
$startTime = time();

// Number of times we will generate a random number and check if it is a prime.
$numberOfRandomNumbers = 1E5; // Scientific notation for number 100000

// Iterate the desired number of times and check if random number is prime.
for ($i = 0; $i < $numberOfRandomNumbers; $i++) {
	
	// Generate (large) random number.
	$randomNumber = rand(getrandmax() - 1E5, getrandmax());
	
	// Check if number is prime or not.
	$isPrime = isPrime($randomNumber);
	
}

// Save the time when the script stopped running.
$endTime = time();

// Display the number of seconds the script was running.
echo $endTime - $startTime . "\n";

/**
 * Check if number is prime or not.
 * @param int $number Number to check. 
 * @return boolean True if number is prime, else false.
 */
function isPrime($number) {
  
	// Check lower boundaries on primality
	if( $number == 2 ){ 
		return true;
	} // 1 is not prime, even numbers > 2 are not prime
	else if( $number == 1 || ($number & 1) == 0){
		return false;
	}

	// Check for primality using odd numbers from 3 to sqrt(n)
	for($i = 3; $i <= sqrt($number); $i += 2){
		// number is not prime if it is evenly divisible by some 'i' in this range
		if( fmod($number, 2) == 0 ){
			return false;
		}
	}
  
	// Number is prime
	return true;
}