What are all the differences between the "Late 2012" Aluminum iMac models and the "Mid-2011" models that they replaced?

Please note that the "Mid-2011" and "Late 2012" Aluminum iMac models all have been discontinued. However, this Q&A has been updated subsequently and is quite useful for anyone buying or selling one of these models on the used market.

With a casual glance of the front of each, it would be easy to mistake the "Late 2012" 21.5-Inch Aluminum iMac models -- the standard configurations of which are the iMac "Core i5" 2.7 21.5-Inch and "Core i5" 2.9 21.5-Inch -- and the "Mid-2011" 21.5-Inch models replaced -- the iMac "Core i5" 2.5 21.5-Inch and "Core i5" 2.7 21.5-Inch.

Likewise, it would be easy to mistake the "Late 2012" 27-Inch Aluminum iMac models -- the standard configurations of which are the iMac "Core i5" 2.9 27-Inch and "Core i5" 3.2 27-Inch -- and the "Mid-2011" 27-Inch models replaced -- the iMac "Core i5" 2.7 27-Inch and "Core i5" 3.1 27-Inch.

With a more detailed inspection, though, it is obvious that the "Late 2012" models use a completely different case design that is considerably thinner. Specifically, Apple promo copy noted that the "Late 2012" models occupy "40% less volume" than their predecessors.

However, the thinner "Late 2012" models have a number of compromises -- particularly the 21.5-Inch models -- and a detailed comparison between the lines is particularly worthwhile as a result.

Photo Credit: Apple, Inc. (21.5" & 27" Late 2012 iMac, Left & Right, Respectively)

External Differences

Both lines use all aluminum cases with the entire computer hidden behind the display, but the "Mid-2011" models have a thicker design with a flat edge, roughly an inch thick, at the sides of the display. By contrast, the "Late 2012" iMac models sharply taper to just 5 mm at the edges of the display. Neither line has seams, but Apple notes that the front and back of the "Late 2012" iMac models are so thin that the company had to implement "friction-stir welding" -- which uses a "combination of intense friction-generated heat and pressure to intermix the molecules of the two aluminum surfaces."

The displays used in both the "Mid-2011" and "Late 2012" models are the exact same 8-bit 16:9 LED-backlit TFT Active Matrix LCDs complete with IPS (In-Plane Switching) technology and 178 degrees horizontal and vertical viewing angles. However, the "Mid-2011" models have a glossy piece of glass over the display whereas the "Late 2012" models have a glass cover that is fully laminated to the LCD itself, which means that reflections reportedly are reduced by approximately 75%, but that it is not possible to replace the display or the glass independently from one another.

The "Mid-2011" and "Late 2012" models all have an integrated 720p "FaceTime HD" webcam at the top of the display and speakers mounted under the display, although the "Late 2012" models have dual integrated microphones rather than just one. On the other hand, the "Mid-2011" models have an integrated optical drive on the right hand side of the display whereas the "Late 2012" models do not have an integrated optical drive, although an external one could be added at extra cost (site sponsor Adorama has the official external Apple SuperDrive for US$79 and Other World Computing has a variety of third-party external optical drive options).

The 21.5-Inch "Mid-2011" iMac models are not VESA compliant, but the 27-Inch "Mid-2011" models are, and can be easily wall mounted after purchase with a VESA mount kit. These 27-Inch models can easily be converted back and forth between the traditional desk stand and a wall-mount option. None of the "Late 2012" models, however, are VESA compliant, but both sizes can be configured with a wall mount option instead of the aluminum stand at the time of purchase. If a "Late 2012" iMac model is configured for wall mounting, it does not ship with the traditional stand, and cannot be reconfigured for desk use.

By default, all of the "Mid-2011" and "Late 2012" iMac models included a notebook size aluminum wireless keyboard without a numeric keypad and the choice of either a wireless "Magic Mouse," where the "entire top is a seamless multi-touch surface" that allows one to "navigate using intuitive finger gestures" or a "Magic Trackpad" that provides multi-touch input like on a recent Apple notebook.

Connectivity Differences

There are significant differences in connectivity between the "Mid-2011" and the "Late 2012" iMac lines.

All of these systems have an SDXC-capable SD card slot, Gigabit Ethernet, and built-in "MIMO" 450 Mbit/sec 802.11a/b/g/n wireless networking (which Apple used to refer to as AirPort Extreme), but otherwise connectivity is different.

The "Mid-2011" models have four USB 2.0 ports, a Firewire "800" port, Bluetooth 2.1+EDR, and separate audio line in and out ports. The 21.5-Inch "Mid-2011" models also have one Thunderbolt port whereas the 27-Inch models have two. By contrast, the "Late 2012" models have four USB 3.0 ports, Bluetooth 4.0, and a single "headphone/optical digital audio output (minijack)" that also supports the Apple iPhone headset with microphone. Regardless of display size, the "Late 2012" models have two Thunderbolt ports, but they lack a Firewire "800" port.

Thunderbolt is capable of powering an external display up to 30" (2560x1600) or other peripherals that support the Thunderbolt standard. Both the "Mid-2011" and "Late 2012" iMac models support "Target Display Mode" from external Thunderbolt-equipped sources so they can be used as an external display from another Thunderbolt-equipped Mac).

Identification Differences

The "Mid-2011" and "Late 2012" iMac models share Model Numbers with other systems, but not with each other. Specifically, the 21.5-Inch and 27-Inch "Mid-2011" iMac models use the A1311 and A1312 model numbers, respectively, but so do other systems before them. The 21.5-Inch and 27-Inch "Late 2012" models use the A1418 and A1419 model numbers, respectively, as do later models.

Consequently, the model number is not sufficient to identify the precise series or the precise model. To identify the precise series, which is sufficient for many tasks such as upgrading the RAM in either line, the EMC Number or Model Identifier is easier.

The 21.5-Inch and 27-Inch "Mid-2011" models are EMC number 2428 and 2429, respectively, whereas the "Late 2012" iMac models are EMC number 2544 and 2546, respectively. Just as the site has for other models for many years, EveryMac.com has meticulously hand documented these details for your convenience.

In software, the 21.5-Inch and 27-Inch "Mid-2011" models are model identifier iMac12,1 and iMac12,2, respectively, whereas the "Late 2012" models are model identifier iMac13,1 and iMac13,2, respectively.

Finally, EveryMac.com's Ultimate Mac Lookup feature additionally can uniquely identify each one of the "Mid-2011" and "Late 2012" iMac models by their serial numbers.

Internal Differences

Internally, the "Mid-2011" and "Late 2012" iMac lines have significant processor, graphics processor, architecture, and RAM differences.

The "Mid-2011" models have Quad Core "Sandy Bridge" processors and Radeon HD graphics whereas the "Late 2012" models have faster Quad Core "Ivy Bridge" processors and GeForce GT or GTX graphics. However, both lines have the processor mounted on an LGA 1155 (H2) processor socket and each also has a "Direct Media Interface" (DMI) that "connects between the processor and chipset" in lieu of a traditional system bus that Intel reports runs at 5 GT/s.

Officially, all "Mid-2011" iMac models support up to 16 GB of RAM using 204-pin 1333 MHz PC3-10600 DDR3 SO-DIMMs and all have four RAM slots, but third-parties have determined that the 27-Inch models actually are capable of supporting up to 32 GB. The "Mid-2011" models all have RAM that is easy to upgrade via an access panel under the display edge.

The "Late 2012" iMac models use faster 204-pin 1600 MHz PC3-12800 DDR3 SDRAM SO-DIMMs, although the 21.5-Inch models only have two RAM slots and support 16 GB of RAM whereas the 27-Inch models have four RAM slots and support 32 GB of RAM. Officially, Apple does not intend for one to upgrade the RAM in the 21.5-Inch models after initial purchase at all -- and doing so effectively requires disassembly -- but it is possible. The 27-Inch models, by contrast, have a "pop off" door on the back that makes upgrading the RAM quick and easy.

The "Mid-2011" and "Late 2012" models both support a 2.5" 6 Gb/s Serial ATA (Revision 3.0) hard drive or SSD. As noted earlier, the "Mid-2011" iMac models have an internal optical drive as well. It is not simple to upgrade the storage in either line.

Comparison Charts

The major differences between the 21.5-Inch and 27-Inch "Mid-2011" and "Late 2012" Aluminum iMac models are summarized below. Please refer to the specs page for the model of interest for complete details.

21.5-Inch "Mid-2011" & "Late 2012" iMac Differences

	21.5" iMac (Mid-2011)	21.5" iMac (Late 2012)
Processor Speed:	2.5 GHz, 2.7 GHz*	2.7 GHz, 2.9 GHz**
Processor Type:	Quad Core i5*	Quad Core i5**
Processor Family:	Sandy Bridge	Ivy Bridge
Shared L3 Cache:	6 MB*	6 MB**
RAM Type:	1333 MHz PC3-10600 DDR3	1600 MHz PC3-12800 DDR3
Standard RAM:	4 GB	8 GB
Maximum RAM:	16 GB	16 GB
RAM Slots:	4	2
RAM Upgrade:	Easy (Door)	Difficult (Hack)
Standard Storage:	500 GB, 1 TB	1 TB
Standard Graphics:	Radeon HD 6750M/6770M	GeForce GT 650M
Dedicated VRAM:	512 MB (GDDR5)	512 MB (GDDR5)
Display Size:	21.5-Inch	21.5-Inch
Display Resolution:	1920x1080	1920x1080
Display Finish:	Glossy	Anti-Glare
Display Glass:	Removable	Fully Laminated
Internal Optical Drive:	Yes	No
Thunderbolt Ports:	Yes (1)	Yes (2)
USB Ports:	2.0 (4)	3.0 (4)
Firewire "800":	Yes (1)	No
Bluetooth:	Yes (2.1+EDR)	Yes (4.0)
VESA Option:	No	Yes
Dimensions:	17.75 x 20.8 x 7.42	17.7 x 20.8 x 6.9
Weight:	20.5 lbs. (9.3 kg)	12.5 lbs. (5.68 kg)
Order Number (US):	MC309LL/A, MC812LL/A	MD093LL/A, MD094LL/A
EMC Number:	2428	2544
Model Identifier:	iMac12,1	iMac13,1
Original Price (US):	US$1199, US$1499	US$1299, US$1499

* The MC812LL/A configuration of the "Mid-2011" system additionally could be equipped with a 2.8 GHz Quad Core "Core i7" processor (I7-2600S) for an extra US$200. EveryMac.com also has documented this custom configuration as its own model.

** The MD094LL/A configuration of the "Late 2012" system additionally could be equipped with a 3.1 GHz Quad Core "Core i7" processor (I7-3770S) for an extra US$200. EveryMac.com also has documented this custom configuration as its own model.

27-Inch "Mid-2011" & "Late 2012" iMac Differences

	27" iMac (Mid-2011)	27" iMac (Late 2012)
Processor Speed:	2.7 GHz, 3.1 GHz*	2.9 GHz, 3.2 GHz**
Processor Type:	Quad Core i5*	Quad Core i5**
Processor Family:	Sandy Bridge	Ivy Bridge
Shared L3 Cache:	6 MB*	6 MB**
RAM Type:	1333 MHz PC3-10600 DDR3	1600 MHz PC3-12800 DDR3
Standard RAM:	4 GB	8 GB
Maximum RAM:	32 GB	32 GB
RAM Slots:	4	4
RAM Upgrade:	Easy (Door)	Easy (Door)
Standard Storage:	1 TB	1 TB
Standard Graphics:	Radeon HD 6770M/6970M	GeForce GT 660M/GTX 675MX
Dedicated VRAM:	512 MB/1 GB (GDDR5)	512 MB/1 GB (GDDR5)
Display Size:	27-Inch	27-Inch
Display Resolution:	2560x1440	2560x1440
Display Finish:	Glossy	Anti-Glare
Display Glass:	Removable	Fully Laminated
Internal Optical Drive:	Yes	No
Thunderbolt Ports:	Yes (2)	Yes (2)
USB Ports:	2.0 (4)	3.0 (4)
Firewire "800":	Yes (1)	No
Bluetooth:	Yes (2.1+EDR)	Yes (4.0)
VESA Option:	Yes (Fully Compatible)	Yes
Dimensions:	20.4 x 25.6 x 8.15	20.3 x 25.6 x 8
Weight:	30.5 lbs. (13.8 kg)	21 lbs. (9.54 kg)
Order Number (US):	MC813LL/A, MC814LL/A	MD095LL/A, MD096LL/A
EMC Number:	2429	2546
Model Identifier:	iMac12,2	iMac13,2
Original Price (US):	US$1699, US$1999	US$1799, US$1999

* The MC814LL/A configuration of the "Mid-2011" system additionally could be configured with a 3.4 GHz Quad Core "Core i7" processor (I7-2600) for an extra US$200. EveryMac.com also has documented this custom configuration as its own model.

** The MD096LL/A configuration of the "Late 2012" system additionally could be configured with a 3.4 GHz Quad Core "Core i7" processor (I7-3770) for an extra US$200. EveryMac.com also has documented this custom configuration as its own model.

Comparison Summary

Ultimately, the "Late 2012" Aluminum iMac models may be a "two steps forward, one step back" option compared to the "Mid-2011" line for some users.

Just about everyone should be pleased with the increased performance and reduced display glare that the "Late 2012" models provide, and many may prefer the sleeker look, but for some the difficult to upgrade RAM in the 21.5-Inch models in particular as well as the more difficult to remove display and inflexible VESA setup may be major drawbacks. Others also may like the internal optical drive and the Firewire "800" port that the "Mid-2011" models provide, particularly given even lower prices on the used market.

Used iMac Purchase Options

There are any number of places to purchase a used "Mid-2011" or "Late 2012" iMac. However, purchasing from a quality vendor with extensive experience in the Mac market -- and after sales support -- will provide the best experience and save you money and time, too.

In the US, site sponsor Adorama sells new iMac models with free shipping. Other World Computing sells used and refurb iMac models at bargain prices with free shipping, as well. Finally, if you need to sell an iMac, A+ BBB-rated Cash for Your Mac will buy your older iMac with an instant quote and prompt payment.

In the UK, site sponsor Hoxton Macs sells used iMac models with a one-year warranty and free next day delivery throughout the UK. Delivery across Europe also is available starting at just £9.99 for two-day delivery to France and Germany.

Please also see EveryMac.com's Ultimate Mac Comparison feature to dynamically compare any iMac model to any other Mac.