previews were subsequently released, with Lion Preview 4 (11A480b) being released at WWDC 2011. [9] System requirements x86-64   CPU  ( 64-bit  Macs, with an  Intel Core 2 Duo ,  Intel Core i3 ,  Intel Core i5 ,  Intel Core i7 , or  Xeon  processor.) [14] [21] At least 2GB of RAM [22] Mac