Apple iMac "Core i5" 2.5 21.5-Inch (Mid-2011) Specs
Identifiers: Mid-2011 - MC309LL/A - iMac12,1 - A1311 - 2428
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The iMac "Core i5" 2.5 21.5-Inch Aluminum (Mid-2011) is powered by a Quad Core 2.5 GHz Intel "Core i5" I5-2400S (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 500 GB (7200 RPM) hard drive, a vertically-mounted slot-loading DVD±R DL "SuperDrive", and AMD Radeon HD 6750M 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.
- What are the differences between the "Mid-2011" Aluminum iMac models?
- How do the "Mid-2011" Aluminum iMac models compare to the "Mid-2010" models that preceded them?
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- Tech Specs
- Global Original Prices
- Popular Q&As
Click on the category for related details. The most commonly needed info is "open" by default, but all info is important.
||May 3, 2011
||October 23, 2012
||The "Introduction Date" refers to the date a model was introduced via press release. The "Discontinued Date" refers to the date a model either was replaced by a subsequent system or production otherwise ended.
Also see: All Macs introduced in 2011.
||1 (4 Cores)
|Geekbench 2 (32):
||Geekbench 2 (64):
||Geekbench 2 benchmarks are in 32-bit and 64-bit modes, respectively. These numbers reflect an average of user provided 32-bit and 64-bit results as submitted to the Geekbench website. Higher numbers are better.
You also might be interested in reviewing all 32-bit and 64-bit Geekbench 2 user submissions for Macs with the iMac12,1 Model Identifier, which may include multiple models.
To dynamically compare Geekbench 2 results from different Macs side-by-side, see EveryMac.com's Ultimate Mac Comparison.
|Geekbench 3 (32):
||Geekbench 3 (32):
||These Geekbench 3 benchmarks are in 32-bit mode and are for a single processor core and all processor cores, respectively. Both numbers reflect an average of user provided results as submitted to the Geekbench website. Higher numbers are better.
You also might be interested in reviewing all 32-bit single core and multicore Geekbench 3 user submissions for Macs with the iMac12,1 Model Identifier, which may include multiple models.
To dynamically compare 32-bit Geekbench 3 results from different Macs side-by-side, see EveryMac.com's Ultimate Mac Comparison.
|Geekbench 3 (64):
||Geekbench 3 (64):
||These Geekbench 3 benchmarks are in 64-bit mode and are for a single processor core and all processor cores, respectively. Both numbers reflect an average of user provided results as submitted to the Geekbench website. Higher numbers are better.
You also might be interested in reviewing all 64-bit single core and multicore Geekbench 3 user submissions for Macs with the iMac12,1 Model Identifier, which may include multiple models.
To dynamically compare 64-bit Geekbench 3 results from different Macs side-by-side, see EveryMac.com's Ultimate Mac Comparison.
||Core i5 (I5-2400S)
||This model is powered by a 32 nm, 64-bit Intel Core i5 "Sandy Bridge" processor with quad cores (four independent processor cores on a single silicon chip, each with one thread). Each core has a dedicated 256k level 2 cache and all processor cores share a single 6 MB level 3 cache It also supports Turbo Boost 2.0 (up to 3.3 GHz) -- which "automatically boosts the processor speed based on workload" (so if an application is only using one of the four cores it will automatically increase the speed of the core in use and turn off the unused cores).
Also see: How much faster are the "Mid-2011" Aluminum iMac models than the "Mid-2010" models?
|| Custom Speeds:
||LGA 1155 (Socket H2)*
||*Officially, Apple provides no information about whether or not the processor in this model can be upgraded and the company does not intend for one to upgrade the processor either. However, this processor supports an LGA 1155 (H2) socket and it is possible to upgrade the processor to some extent.
Also see: Is it possible to upgrade the processor in the Aluminum iMac models?
|System Bus Speed:
||Cache Bus Speed:
||2.5 GHz (Built-in)
||*This system has a "Direct Media Interface" (DMI) that "connects between the processor and chipset" in lieu of a traditional system bus. Intel reports that it runs at 5 GT/s.
||256k (x 4), 6 MB
||Each core has its own dedicated 256k level 2 cache and the system has 6 MB of shared level 3 cache.
||Min. RAM Speed:
||Supports 1333 MHz PC3-10600 DDR3 SO-DIMMs (204-pin).
Also see: How do you upgrade the RAM in this Aluminum iMac model? How much RAM does it actually support?
||By default, 4 GB of RAM is installed as two 2 GB SO-DIMM modules. Two slots free.
*Officially, this model supports four 4 GB modules -- one in each slot for a maximum of 16 GB of memory. However, third-parties have discovered that it actually will support 32 GB of memory using four 8 GB modules.
In the US (and many other countries), site sponsor Other World Computing sells memory -- as well as other upgrades -- for this iMac.
In the UK, site sponsor Flexx sells memory and other upgrades for this iMac.
In Australia, site sponsor RamCity sells memory and other upgrades for this iMac.
In Southeast Asia, site sponsor SimplyMac.sg sells memory and other upgrades for this iMac.
Also see: Actual Max RAM of All G3 & Later Macs.
||Radeon HD 6750M
||This model has an AMD Radeon HD 6750M graphics processor with 512 MB of dedicated GDDR5 memory.
Also see: What type of video processor is provided by the Aluminum iMac systems? Is it upgradable?
||This model has 512 MB of dedicated GDDR5 video memory.
||21.5" 16:9 Widescreen
||This model has a 21.5" glossy LED-backlit 16:9 widescreen TFT active matrix display with "IPS technology" and a native resolution of 1920x1080. Apple also reports a viewing angle of 178 degrees horizontal and 178 degrees vertical. The contrast ratio is 1000:1.
|2nd Display Support:
||2nd Max. Resolution:
||Apple reports that this model simultaneously supports the native resolution of the built-in display and up-to a 30-inch external display (2560x1600).
|Standard Hard Drive:
||500 GB (7200 RPM)
||Int. HD Interface:
||Serial ATA (6 Gb/s*)
||*As shipped, these models only supported the 3 Gb/s Serial ATA 2.0 standard for both a 3.5" hard drive and a 2.5" SSD. However, as first discovered by site sponsor OWC, the iMac EFI Update 1.6, released two days later, quietly provided 6 Gb/s Serial ATA 3.0 support.
Also see: How do you upgrade the hard drive in the "Late 2009," "Mid-2010" and "Mid-2011" Aluminum iMac models? What type of storage do they support? Is it even possible to upgrade these models?
In the US (and many other countries), site sponsor Other World Computing sells storage upgrades for this iMac.
In the UK, site sponsor Flexx sells storage upgrades for this iMac.
In Australia, site sponsor RamCity sells storage upgrades for this iMac.
||8X DL "SuperDrive"
||Apple reports that the slot-loading 8X "SuperDrive" with 4X double-layer burning (DVD+R DL/DVD±RW/CD-RW) "writes DVD+R DL discs at up to 4x speed, writes DVD-R and DVD+R discs at up to 8x speed, writes DVD-RW at up to 6x and DVD+RW discs at up to 8x speed, reads DVDs at up to 8x speed, writes CD-R discs at up to 24x speed, writes CD-RW discs at up to 16x speed, [and] reads CDs at up to 24x speed."
||802.11a/b/g/n (450 Mbit*)
||AirPort Extreme (802.11a/b/g/n) and Bluetooth 2.1+EDR standard. Although Apple formally makes no mention of it, as first discovered by HardMac, this model unofficially supports 450 Mbit/sec 802.11n Wi-Fi using MIMO.
|| Firewire Ports:
||Four USB 2.0 ports and one Firewire "800" port (7 watts).
||SDXC SD Card
||In the US (and many other countries), site sponsor Other World Computing sells a wide variety of external expansion options and hand-picked accessories like external storage, stands, keyboards, cables, adapters, speakers, and more for this iMac.|
In Australia, site sponsor Macfixit offers an extensive selection of external expansion options and accessories like docks, stands, chargers, keyboards, security products, and more for this iMac.
||Apple Wireless Keyboard
||This model shipped with a small aluminum "ultrathin, compact wireless keyboard" (no numeric keypad) and a choice of either the wireless "Magic Mouse", where the "entire top is a seamless multi-touch surface" that allows one to "navigate using intuitive finger gestures" or a wireless "Magic Trackpad" that provides multi-touch input like on a recent Apple notebook.
Also see: How does the "ultra thin" keyboard provided with the "Aluminum" iMac models compare to a more traditional desktop keyboard? How does it feel?
||iMac (Late 2009)
||The external case used by the "Mid-2011" iMac models essentially is identical to the one first introduced by the "Late 2009" line with "edge-to-edge glass" for the display and a "seamless all aluminum enclosure."
|Apple Order No:
||The Apple order number should be unique to this system.
|Apple Model No:
||A1311 (EMC 2428)
||Please note that these identifiers refer to more than one model.
Also see: All Macs with the A1311 Model Number, the 2428 EMC Number, and the iMac12,1 Model Identifier.
For more about these identifiers and how to locate them on each Mac, please refer to EveryMac.com's Mac Identification section.
||X 10.6.6 (10J4026)
||*This system fully supports the last version of OS X 10.8 "Mountain Lion", OS X 10.9 "Mavericks", and OS X 10.11 "Yosemite" except for Power Nap functionality. It also supports the last version of OS X 10.11 "El Capitan" -- including Mac-to-Mac AirDrop and AirPlay Mirroring capability -- but no other advanced features are supported including Metal graphics acceleration. It is capable of running macOS Sierra (10.12) as well, although it does not support the Universal Clipboard, Auto Unlock, or Apple Pay features.
Please note that OS X "Lion" 10.7 and subsequent versions of OS X are not capable of running Mac OS X apps originally written for the PowerPC processor as these operating systems do not support the "Rosetta" environment. To run PowerPC applications on this Mac, it will be necessary to use Mac OS X 10.6 "Snow Leopard".
Also see: Which Macs are compatible with macOS Sierra (10.12)? What are the system requirements? Which Macs support which features?
||*Apple's Boot Camp 4 supports the 32-bit version of Windows 7 on this model and Boot Camp 5 supports the 64-bit versions of Windows 7 and Windows 8. Earlier versions of Windows are not supported.
Although Apple does not support Windows 10 via Boot Camp 5 (officially or otherwise), this system meets Microsoft's hardware requirements and it very well may be possible to boot Windows 10 on this Mac. If you have installed Windows 10 on this system (successfully or unsuccessfully), please share the results of your experiment. Thank you.
|MacOS 9 Support:
||Also see: Are there any third-party programs to run Mac OS 9/Classic applications on Intel Macs?
Site sponsor OHS specializes in heavily upgraded Macs capable of running both Mac OS X and Mac OS 9 applications.
For more on running Windows on Intel Macs, please refer to the exhaustive Windows on Mac Q&A.
||17.75 x 20.8 x 7.42
||20.5 lbs. (9.3 kg)
||In inches - height by width by depth, (45.1 cm, 52.8 cm, 18.85 cm).
|Original Price (US):
||Est. Current Retail:
||Please note that on average the estimated current retail pricing of used systems is updated twice a year (please refer to the date on the bottom of the page for the date last updated).
Photo Credit: Apple, Inc.
Global original prices for the iMac "Core i5" 2.5 21.5-Inch (Mid-2011) in 34 different countries and territories follow; organized alphabetically by region.
For global original prices for Intel Macs in one particular country on a single page, please refer to EveryMac.com's Global Original Prices section.
Original Prices - North & South America
Original Prices - Europe
Original Prices - Asia
Original Prices - Australia & New Zealand
If you have additional original prices for this model, please get in touch. Thank you.
Ten of the most popular Q&As about the iMac models follow.
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