What are all the differences between the "Late 2013" Aluminum iMac models and the "Late 2012" models that they replaced?

Please note that the "Late 2012" and "Late 2013" iMac models have been discontinued. However, this Q&A has been updated subsequently and can be quite helpful to anyone buying or selling one of these systems on the used market.

With even a detailed external inspection of the Aluminum iMac models, it is practically impossible to visually differentiate between the "Late 2012" and "Late 2013" lines.

However, this does not mean that there are not important differences between the "Late 2012" models -- the iMac "Core i5" 2.7 21.5-Inch, "Core i5" 2.9 21.5-Inch, "Core i7" 3.1 21.5-Inch, "Core i5" 2.9 27-Inch, "Core i5" 3.2 27-Inch, and "Core i7" 3.4 27-Inch -- and the "Late 2013" models that replaced them -- the iMac "Core i5" 2.7 21.5-Inch, "Core i5" 2.9 21.5-Inch, "Core i7" 3.1 21.5-Inch, iMac "Core i5" 3.2 27-Inch, "Core i5" 3.4 27-Inch and "Core i7" 3.5 27-Inch.

In fact, there are important technical differences, it is just that they are internal. Because the external appearance is so similar, identification differences are particularly critical, too. Consequently, a detailed comparison between the lines can be quite useful.

Photo Credit: Apple, Inc. (21.5" & 27" Late 2013 iMac, Left & Right, Respectively)

External Differences (or Lack Thereof)

For all practical purposes, the "Late 2012" and "Late 2013" iMac lines use the same case. Both use the same all aluminum design that sharply tapers to a 5 mm edge at the sides of the display.

Both lines use the exact same "anti-reflective" 8-bit 16:9 LED-backlit TFT Active Matrix LCDs with IPS (In-Plane Switching) technology and 178 degree horizontal and vertical viewing angles. Both also have the same glass cover that is fully laminated to the LCD itself. This lamination means that reflections are reduced, but it also means that the display and the glass only can be replaced as a single piece, which is more complicated and costly to replace than systems that have a separate display and external glass cover.

Both lines additionally have an integrated 720p "FaceTime HD" webcam embedded in the upper display bezel, speakers integrated at the bottom edge of the display, and dual integrated microphones. Neither has an integrated optical drive, although an external one may be added at additional 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).

Neither the "Late 2012" nor the "Late 2013" lines -- regardless of display size -- are VESA compliant, but all could be configured with a wall mount option instead of the aluminum stand at the time of purchase for an additional US$40. If one of these iMac models was configured for wall mounting, it did not ship with the traditional stand, and it cannot subsequently be reconfigured for desk use.

By default, both lines shipped with a notebook size aluminum wireless keyboard without a numeric keypad and the choice of either the wireless "Magic Mouse" (which has the entire top as "a seamless multi-touch surface" that allows one to "navigate using intuitive finger gestures") or the "Magic Trackpad" (which provides multi-touch input like on a recent Apple notebook), but for the "Late 2013" line Apple also offered the option of a traditional wired Apple mouse.

Connectivity Differences

There is one important connectivity difference between the "Late 2012" and "Late 2013" iMac lines.

All of these systems have an SDXC-capable SD card slot, four USB 3.0 ports, two Thunderbolt ports -- which support Mini DisplayPort output for two external displays up to 30" (2560x1600) as well as "Target Display Mode" via Thunderbolt -- one Gigabit Ethernet port (10/100/1000Base-T), one "headphone/optical digital audio output (minijack)" that also supports the Apple iPhone headset with microphone, and support for Bluetooth 4.0.

However, the "Late 2013" iMac systems also support 802.11ac Wi-Fi, whereas the "Late 2012" iMac systems only support slower "MIMO" 450 Mbit/sec 802.11a/b/g/n Wi-Fi.

Identification Differences

The "Late 2012" and "Late 2013" iMac lines share Model Numbers. Specifically, the 21.5-Inch systems share model number A1418 and the 27-Inch systems share model number A1419.

The model numbers are not precise enough to uniquely identify specific models. Consequently, other identifiers are better for more precision. Just as the site has for other models for many years, EveryMac.com has meticulously hand documented all of these details for your convenience.

Externally, the EMC Number is best as it is less likely to be shared by future models using the same case type. The 21.5-Inch and 27-Inch "Late 2012" iMac models are EMC number 2544 and 2546, respectively. For the "Late 2013" line, the Iris-equipped iMac "Core i5" 2.7 21.5-Inch is EMC number 2638 and the iMac "Core i5" 2.9 21.5-Inch and "Core i7" 3.1 21.5-Inch models with dedicated graphics are EMC number 2742. All 27-Inch "Late 2013" iMac models share EMC number 2639.

In software, the 21.5-Inch and 27-Inch "Late 2012" models are model identifier iMac13,1 and iMac13,2, respectively, whereas the "Late 2013" 21.5-Inch iMac models are Model Identifier iMac14,1 and iMac14,3 (again, for the model with Iris graphics and the higher-end models with dedicated graphics, respectively), and the 27-Inch models are iMac14,2.

Finally, EveryMac.com's Ultimate Mac Lookup feature additionally can uniquely identify each one of the "Late 2012" and "Late 2013" iMac models by their serial numbers.

Internal Differences

Internally, the "Late 2012" and "Late 2013" iMac lines have significant processor, graphics processor, architecture, and upgrade-related differences.

In fact, just about the only internal attribute that the two lines share is that they both use 204-pin 1600 MHz PC3-12800 DDR3 SDRAM SO-DIMMs. In both lines, the 21.5-Inch models 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.

Both lines have Quad Core processors, but the "Late 2012" models use "3rd Gen" Intel processors and the "Ivy Bridge" architecture whereas the "Late 2013" models use faster "4th Gen" Intel processors and the "Haswell" architecture. Among other performance-related improvements, the "Haswell" architecture uses a directly attached "On Package Interface" (OPI) instead of the earlier and slower "Direct Media Interface" (DMI) to connect between the processor and chipset. Graphics processors are different between the lines, also, with the "Late 2013" line generally providing faster graphics performance.

In terms of internal upgrades other than the RAM, as first discovered courtesy of teardowns from iFixit and others, there are some disappointments with both lines.

For storage upgrades, if the 21.5-Inch "Late 2012" iMac models were not configured with an SSD or a "Fusion Drive" at the time of purchase, there is no way to add a PCIe-based "blade" SSD later as the needed connector is not present. However, the 27-Inch "Late 2012" and all "Late 2013" iMac models do have this connector on the motherboard even without a pre-installed SSD, so it is possible to add a PCIe-based "blade" SSD after the purchase of the system.

Both lines have a connector for a 6 Gb/s Serial ATA (Revision 3.0) hard drive or SSD, as well, but it is a pain to upgrade the storage in any of these systems regardless.

For processor upgrades, the situation is partially reversed and the processors in the "Late 2012" models -- regardless of display size -- as well as the 27-Inch "Late 2013" models are mounted on processor sockets, which makes processor upgrades feasible. The 21.5-Inch "Late 2013" models, on the other hand, have the processor soldered and cannot be upgraded at all.

Comparison Charts

The major differences between the 21.5-Inch and 27-Inch "Late 2012" and "Late 2013" Aluminum iMac models are summarized below. Please refer to the specs page for the model of interest for complete details.

21.5-Inch "Late 2012" & "Late 2013" iMac Differences

	21.5" iMac (Late 2012)	21.5" iMac (Late 2013)
Processor Speed:	2.7 GHz, 2.9 GHz*	2.7 GHz, 2.9 GHz**
Processor Type:	Quad Core i5*	Quad Core i5**
Processor Family:	Ivy Bridge	Haswell
Processor Mounting:	LGA 1155 (H2)	Soldered
System Bus:	DMI	OPI
Shared L3 Cache:	6 MB*	4 MB, 6 MB**
RAM Type:	1600 MHz PC3-12800 DDR3	1600 MHz PC3-12800 DDR3
Standard RAM:	8 GB	8 GB
Maximum RAM:	16 GB	16 GB
RAM Slots:	2	2
RAM Upgrade:	Difficult (Hack)	Difficult (Hack)
Standard Storage:	1 TB	1 TB
PCIe SSD Connector:	No	Yes
Standard Graphics:	GeForce GT 650M	Iris Pro 5200 GeForce GT 750M
Dedicated VRAM:	512 MB (GDDR5)	Integrated 1 GB (GDDR5)
Display Size:	21.5-Inch	21.5-Inch
Display Resolution:	1920x1080	1920x1080
Wi-Fi:	802.11a/b/g/n (450 Mbit)	802.11ac
Order Number (US):	MD093LL/A, MD094LL/A	ME086LL/A, ME087LL/A
EMC Number:	2544	2638, 2742
Model Identifier:	iMac13,1	iMac14,1, iMac14,3
Original Price (US):	US$1299, US$1499	US$1299, US$1499

* 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.

** The ME087LL/A configuration of the "Late 2013" system additionally can be equipped with a 3.1 GHz Quad Core "Core i7" processor (I7-4770S) for an extra US$200. EveryMac.com also has documented this custom configuration as its own model.

27-Inch "Late 2012" & "Late 2013" iMac Differences

	27" iMac (Late 2012)	27" iMac (Late 2013)
Processor Speed:	2.9 GHz, 3.2 GHz*	3.2 GHz, 3.4 GHz**
Processor Type:	Quad Core i5*	Quad Core i5**
Processor Family:	Ivy Bridge	Haswell
Processor Mounting:	LGA 1155 (H2)	LGA 1150 (H3)
System Bus:	DMI	OPI
Shared L3 Cache:	6 MB*	6 MB**
RAM Type:	1600 MHz PC3-12800 DDR3	1600 MHz PC3-12800 DDR3
Standard RAM:	8 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
PCIe SSD Connector:	Yes	Yes
Standard Graphics:	GeForce GT 660M GeForce GTX 675MX	GeForce GT 755M GeForce GTX 775M
Dedicated VRAM:	512 MB (GDDR5) 1 GB (GDDR5)	1 GB (GDDR5) 2 GB (GDDR5)
Display Size:	27-Inch	27-Inch
Display Resolution:	2560x1440	2560x1440
Wi-Fi:	802.11a/b/g/n (450 Mbit)	802.11ac
Order Number (US):	MD095LL/A, MD096LL/A	ME088LL/A, ME089LL/A
EMC Number:	2546	2639
Model Identifier:	iMac13,2	iMac14,2
Original Price (US):	US$1799, US$1999	US$1799, US$1999

* 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.

** The ME089LL/A configuration of the "Late 2013" system additionally can be configured with a 3.5 GHz Quad Core "Core i7" processor (I7-4771) for an extra US$200. EveryMac.com also has documented this custom configuration as its own model.

Comparison Summary

Ultimately, the "Late 2013" iMac models are a modest update compared to the "Late 2012" iMac models replaced, but the improved performance, faster Wi-Fi, the option of faster storage (and the improved storage upgrade possibilities) are likely to be welcomed by most users.

However, for those interested in saving a bit of money, the "Late 2012" iMac models remain well worth consideration, particularly given discount prices on the used market.

New & Used iMac Purchase Options

There are no shortage of places to purchase a used "Late 2012" or "Late 2013" iMac. However, purchasing from a quality vendor with extensive experience in the Mac market -- and after sales support -- is the best option and will 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.