text: 400 it's a minimum this days .. if u planing to upgrade renew ur sistem remember that the new hardwares are using a lot of eletricity ... so if u dont want to have problems which u definettly will if u use a 200psu go for the 400 or better .. u can use an 600 W psu .. the bigger the better but that only if u'll use 2graphic card's, 4hdd's, 3dvdroms etc :p