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 with a dedicated 256k level 2 cache for each core and an 8 MB shared level 3 cache.
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 (2560×1440 native) display “with IPS technology”.£509.99
The iMac “Core i5” 3.1 27-Inch Aluminum (Mid 2011) features a 22 nm Quad Core 3.1 GHz Intel “Center i5” I5-3407S (Ivy Bridge) processor with four independent processor centers on a single chip, a 6 MB shared level 3 cache, 8 GB of 1600 MHz DDR3L SDRAM (PC3-12800) installed in pairs (two 4 GB modules), a 1 TB (7200 RPM) hard drive, and a NVIDIA GeForce GTX 660M graphics processor with 512 MB of dedicated GDDR5 memory. It also has a built-in “FaceTime HD” webcam and stereo speakers, but lacks an optical drive. This model has a 27″ 2560×1440 LED-backlit 16:9 widescreen IPS display with the “cover glass fully laminated to the LCD and anti-intelligent coating.” The rear of the case is aluminum and is thicker in the center and tapers to a razor thin 5 mm at the edges.£539.99
The iMac “Core i7” 2.93 27-Inch (Mid-2009) originally was offered as a “configure-to-order” configuration of the iMac “Core i5” 2.8 27-Inch (Mid-2009), but it later was offered as a standard configuration, as well.Other than processor, these two models are identical. The iMac “Core i7” 2.93 27-Inch Aluminum (Mid-2009) is powered by a Quad Core 2.93 GHz Intel “Core i7” I7-870 (Lynnfield) processor with a dedicated 256k level 2 cache for each core and an 8 MB shared level 3 cache. In lieu of a system bus, it has a “Direct Media Interface” (DMI) that “connects between the processor and chipset” at 2.5 GT/s. By default, it is configured with 8 GB of RAM (1333 MHz PC3-10600 DDR3 SDRAM), a 1TB (7200 RPM) , ATI Radeon HD 5750 graphics with 1 GB of dedicated GDDR5 memory.£569.99