Javascript Desempenho entre typeof e direct

gistfile1.txt

var loops = 1e8,
    foo;

console.time('typeof');
while(loops--) {
    if( typeof foo !== 'undefined' ) {}
}
console.timeEnd('typeof');

loops = 1e8;

console.time('direct');
while(loops--) {
    if( foo !== undefined) {}
}
console.timeEnd('direct');