MacBook-Pro-de-Florian-Margaine:v8 florian$ cat first.js
function Blerg() {
      this._a = 5;
}

Blerg.prototype.getA = function() {
      return this._a;
};

Blerg.prototype.setA = function(val) {
      this._a = val;
};

var b;

for (var i = 0; i < 100000; i++) {
    b = new Blerg();
}
MacBook-Pro-de-Florian-Margaine:v8 florian$ cat second.js
function Blerg2() {
  // nothing!
}

Blerg2.prototype._a = 5;

Blerg2.prototype.getA = function() {
  return this._a;
};

Blerg2.prototype.setA = function(val) {
  this._a = val;
};

var b;

for (var i = 0; i < 100000; i++) {
    b = new Blerg2();
}