The iMac "Core i5" 2.7 21.5-Inch Aluminum (Mid-2011) is powered by a Quad Core 2.7 GHz Intel "Core i5" I5-2500S (Sandy Bridge) processor with a dedicated 256k level 2 cache for each core and a 6 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. By default, 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 backward 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.