 In 2009 Asus released the UX50V , a 15 inch laptop that was focused on energy efficiency and had a thin profile . The laptop was rated poorly by reviewers as it under @-@ performed and had mediocre battery life , despite the installed energy efficient hardware . Although not branded as one , it bore the same " UX " product code as many of the later Zenbooks and was an early foray into the ultraportable market . 
