Apple iMac 27-Inch "Core i7" 2.8 (Late 2009)
The iMac "Core i7" 2.8 27-Inch Aluminum (Late 2009) is powered by a 2.8 GHz Quad-Core Intel "Core i7" I7-860 (Lynnfield/Nehalem) processor with a dedicated 256k level 2 cache for each core and an 8 MB shared level 3 cache.
Apple Model No: A1312 (EMC 2374)..
Apple Order number: MC507LL/A.
It also has a built-in iSight video camera and built-in stereo speakers underneath the 27" glossy 16:9 LED-backlit TFT Active Matrix LCD (2560x1440 native) display "with IPS technology".
Connectivity includes four USB 2.0 ports, a Firewire "800" port, built-in AirPort Extreme, and Gigabit Ethernet, as well as a Mini DisplayPort, which supports an external display up to 30" (2560x1600). This model also "supports input from external DisplayPort sources" with adapters, so it can be used as an external display for DisplayPort-equipped devices as well as a computer.
The "Late 2009" iMac line looks similar to earlier Aluminum iMac models but have an "edge-to-edge" glass design and a "seamless all aluminum enclosure" (previous aluminum models have a modest aluminum border around the display and a plastic back).