2.5GHz dual-core Intel Core i5 4GB memory 500GB hard drive Intel HD Graphics 4000 OS X Maverick Sleek aluminum enclosure Dual-core Intel Core i5 or quad-core Intel Core i7 Highly energy efficient Processor 2.5GHz dual-core Intel Core i5 (Turbo Boost up to 3.1GHz) with 3MB L3 cache Wi-Fi 802.11n Wi-Fi wireless networking; IEEE 802.11a/b/g compatible Bluetooth Bluetooth 4.0 wireless technology Electrical and Operating Requirements Line voltage: 100-240V AC Frequency: 50Hz to 60Hz, single phase Maximum continuous power: 85W Operating temperature: 50° to 95° F (10° to 35° C) Storage temperature: -40° to 116° F (-40° to 47° C) Relative humidity: 5% to 95% noncondensing Maximum altitude: tested up to 10,000 feet Typical acoustical performance, sound pressure level (operator position): Dual-core model: 12 dBA at idle Quad-core model: 15 dBA at idle OS X Server quad-core model: 16 dBA at idle