The iMac "Core i5" 2.66 27-Inch Aluminum (Late 2009) is powered by a 2.66 GHz Quad Core Intel "Core i5" I5-750 (Lynnfield/Nehalem) processor, which includes a dedicated 256k level 2 cache per core and an 8 MB shared level 3 cache.
Its default configuration features 4 GB of RAM (1066 MHz PC3-8500 DDR3 SDRAM), a 1 TB (7200 RPM) hard drive, a vertically-mounted slot-loading DVD±R DL "SuperDrive", and an ATI Radeon HD 4850 graphics processor with 512 MB of dedicated GDDR3 memory.
The system also has a built-in iSight video camera and integrated stereo speakers beneath the 27" glossy 16:9 LED-backlit TFT Active Matrix LCD (2560x1440 native) display, which uses "IPS technology".
Connectivity options include four USB 2.0 ports, a Firewire "800" port, built-in AirPort Extreme, and Gigabit Ethernet. It also has a Mini DisplayPort that supports an external display up to 30" (2560x1600). Uniquely, this model also "supports input from external DisplayPort sources" via adapters, allowing it to function as an external display for other devices.
The "Late 2009" iMac line resembles earlier Aluminum models but is distinguished by an "edge-to-edge" glass design and a "seamless all aluminum enclosure," unlike previous versions which had a visible aluminum border and a plastic back.
Key enhancements include LED-backlit displays with "IPS technology" for better quality, four RAM slots supporting up to 16 GB (up from two slots/8 GB), an SD Card slot, and redesigned speakers promising "louder, clearer sound with better bass response and less distortion".
These models shipped with a compact aluminum Apple Wireless Keyboard and the new multi-touch "Magic Mouse," featuring a seamless top surface for intuitive gesture navigation. A new aluminum remote was also available as a US$19 option.