According to http://www.sencha.com/blog/ext-js-4-1-performance, it suggests using for (...) rather than Ext.Array.each.
But, in my experiment, I am so surprised that Ext.Array.each has better performance than for (...). Why?

PHP Code:
        var = [];        
        for ( var 
0100000i++) {
            
r.push(i);
        }

        
time = new Date();
        for ( var 
0r.lengthi++) {
        }
        
console.log(new Date() - time); // 200 ms

        
time = new Date();
        
Ext.Array.each(r, function(rec) {
        });
        
console.log(new Date() - time); // 55 ms