I have 1 laptop already week. I'm very satisfied and I regret my purchase in any way. Price / performance ratio unbeatable. The maximum supported number of memory modules is 2, often not declared on various web pages like 1 (same as with all ASUS X75 / F75 models namely, 1 slot is free). I have installed an additional 4GB memory module, thus the laptop is now running (enormous increase in output) in 8GB Dual mode. For those who are lying have no operating system in the drawer, the ASUS models with final designation H (= Windows) or DU (= Linux) is recommended.