These iMacs are in excellent A stock condition. A fresh copy of Mac OS 10.12 Sierra loaded. 8gb RAM (2 4gb sticks, leaves 2 slots open).
- 21.5-inch LED-backlit glossy widescreen TFT LCD display with IPS, 1920x1080 resolution
- 2.8GHz quad-core Intel Core i7 processor
- 8.0GB (2x4.0GB) PC3-10600 (1333MHz) DDR3 SO-DIMM, supports up to 32.0GB, 2 slots open
- 1.0TB Serial ATA hard disk drive @ 7200RPM
- DVD-RW/CD-RW SuperDrive-DL
- AMD Radeon HD 6770M graphics with 512MB GDDR5 memory
- AirPort Extreme wireless card (802.11a/b/g/n)
- Bluetooth 2.1 + EDR
- Built-in FaceTime HD camera
- 1- Thunderbolt port
- 4- USB 2.0 ports
- 1- FireWire 800 port
- 1- Ethernet port
- 1- Secure Digital (SDXC) slot
- Power Cable Included
The iMac "Core i7" 2.8 21.5-Inch Aluminum (Mid-2011) technically is a "configure-to-order" configuration of the iMac "Core i5" 2.7 21.5-Inch Aluminum (Mid-2011), but also is documented as a separate model for reader convenience. Other than processor (and the corresponding level 3 cache), these two models are identical.
The iMac "Core i7" 2.8 21.5-Inch Aluminum (Mid-2011) is powered by a Quad Core 2.8 GHz Intel "Core i7" I7-2600S (Sandy Bridge) processor with a dedicated 256k level 2 cache for each core and a 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 5 GT/s.
If only the processor is customized, it is configured with 4 GB of RAM (1333 MHz PC3-10600 DDR3 SDRAM), a 1 TB (7200 RPM) hard drive, a vertically-mounted slot-loading DVDR DL "SuperDrive", and AMD Radeon HD 6770M graphics with 512 MB of dedicated GDDR5 memory.
It also has a built-in "FaceTime HD" video camera and built-in stereo speakers underneath the 21.5" glossy 16:9 LED-backlit TFT Active Matrix LCD (1920x1080 native) display "with IPS technology".
Connectivity includes four USB 2.0 ports, a Firewire "800" port, built-in AirPort Extreme, Gigabit Ethernet, and an SDXC card slot as well as a single "Thunderbolt" port that is backwards compatible with Mini DisplayPort and, likewise, supports an external display up to 30" (2560x1600). Thunderbolt also supports other peripherals that use the Thunderbolt standard which provides up to 10 Gbps of bandwidth in both directions.
Externally, the "Mid-2011" iMac line uses the same "edge-to-edge" glass design and "seamless all aluminum enclosure" as the "Mid-2010" models that came before them. Internally, however, the "Mid-2011" line is equipped with faster processors and faster graphics processors, as well as the aforementioned external improvements of a higher resolution (and wider angle) webcam and Thunderbolt port.
The "Mid-2011" iMac models included a compact aluminum Apple Wireless Keyboard and the choice of either a multi-touch "Magic Mouse" or a multi-touch "Magic Trackpad" that "enables users to scroll smoothly up and down a page with inertial scrolling, pinch to zoom in and out, rotate an image with their fingertips and swipe three fingers to flip through a collection of web pages or photos" just like on Apple notebooks from the same era. An aluminum remote was offered for an additional US$19, too.
Detailed Specs From Apple Are Here: