iMac (Intel-based)

At the Macworld Conference and Expo on January 10, 2006, Steve Jobs announced that the new iMac would be the first Macintosh to use an Intel CPU, the Core 2 Duo. The introduction of the new iMac along with the Intel-based MacBook Pro was the start of the Mac transition to Intel processors. In the following months, the other Mac products followed, including the introduction of the Intel Core-powered Mac mini on February 28, 2006, the MacBook consumer line of laptop computers on May 16, 2006, the Mac Pro on August 7, 2006, and the Xserve in November 2006, completing the transition.

The features, price, and case design remained unchanged from the iMac G5. The processor speed, however, according to tests run by Apple using SPEC,[2] was declared to be two to three times faster than the iMac G5.

On June 22, 2020, Apple's Worldwide Developer Conference keynote included the announcement that future Macintosh computers would transition yet again to Apple's own ARM-based processor technology, eliminating the company's use of Intel x86-64 compatible CPUs. The transition was said to take place over a two-year period, with the first "Apple Silicon" Macs shipping to consumers by the end of 2020.[3]

17-inch polycarbonate iMac

Alongside the MacBook Pro, the iMac Core Duo represents Apple's first computer to feature Intel processors instead of PowerPC processors. It retained the style, design, and features of the preceding iMac G5.

In early February 2006, Apple confirmed reports of video display problems on the new Intel-based iMacs. When playing video on Apple's Front Row media browser, some 20-inch iMacs (those built-to-order with upgraded video cards) showed random horizontal lines, ghosting, video tearing and other problems. The problem was fixed with a software update.

In late 2006, Apple introduced a new version of the iMac including a Core 2 Duo chip and a lower price. Apple added a new 24-inch model with IPS-display and a resolution of 1920 × 1200 (WUXGA), making it the first iMac to be able to display 1080p content in its full resolution, and a VESA Flat Display Mounting Interface. Except for the 17-inch 1.83 GHz processor model, this version also included an 802.11n draft card.[4]

17", 20", and 24" iMacs from late 2006

24-inch aluminum iMac

In August 2007, Apple introduced a complete redesign of the iMac, featuring an aluminum, glass and plastic enclosure. There is only one visible screw on the entire computer, located at the base of the iMac for accessing the memory slots. It has a black, plastic backplate that is not user-removable. The 17-inch model was completely removed from the lineup.

In March 2009, Apple released a minor refresh of the iMac line. Changes included a fourth USB port, replacement of two FireWire 400 ports with one FireWire 800 port, replacement of mini-DVI with Mini DisplayPort, and a slightly redesigned base which is thinner. The exterior design was almost identical to the older Intel-based iMacs. The models were one 20-inch configuration and three 24-inch configurations (instead of two at each screen size as before).[17]

Apple doubled the default RAM and hard-disk size on all models, moving the RAM to the DDR3[18] specification. This revision also introduced a new, smaller, and more compact Apple Keyboard that excluded the numeric keypad and forward delete key in favor of the fn + Delete keyboard shortcut by default.[17] Users could, however, replace this version with a more traditional, full-size model with a numeric keypad by requesting Apple to build their machine to order through its online store.

27-inch Unibody iMac

In October 2009, a 16:9 aspect ratio screen was introduced in 21.5" and 27" models, replacing the 20" and 24" 16:10 aspect ratio screens of the previous generation. The back is now a continuation of the aluminum body from the front and sides instead of a separate plastic backplate. Video card options entirely switched to AMD, save for the standard onboard Nvidia card in the base smaller model. The iMac's processor selection saw a significant increase.

The Intel i-series chips are introduced to Mac for the first time on the higher-spec 27-inch models.

Default RAM has also been increased across the iMac range. With the advent of the larger screens, Apple doubled the number of memory slots from two to four. Consequently, the maximum memory capacity was also doubled (to 16 GB),[25] and for Intel Core i-series (27-inch), quadrupled, to 32 GB.

The 27-inch models of the line became the first to offer Target Display Mode, allowing the iMac to be used as an external display for another Mac computer when connected via Mini DisplayPort, a feature that was extended to the 21.5-inch models onwards with the introduction of Thunderbolt.

The Mid-2010 iMac 27" has AMD Radeon HD5650 and HD5750 graphic cards. Both cards cannot support the low-level Metal API, preventing this model from upgrading to Mojave and Catalina. AMD had developed a firmware upgrade that would allowed both graphic cards to support Metal and Mid-2010 iMac to be upgraded to latest macOS, but Apple had refused to certify them.

The Late 2011 Unibody iMac is also the last model to include an internal SuperDrive.

27-inch slim unibody iMac

In October 2012, a new iMac model was introduced that featured a considerably smaller body depth than the previous models, measuring 5mm at its thinnest point, and now without an internal SuperDrive. This was partly achieved by using a process called Full lamination. The display and glass are laminated together, eliminating a 2 mm gap between them. The 21.5 in and 27 in screens remained at their previous resolutions, 1920×1080 and 2560×1440 respectively.

As with the 2009 model, memory has been upgraded; the standard specification is now 8 GB, with the 21.5 in model supporting up to 16 GB and the 27 in model supporting up to 32 GB. It was reported that the 21.5 in iMac would have non-replaceable soldered memory similar to the MacBook Air and Retina display MacBook Pro[35] though tear-downs show that it uses removable memory but accessing the modules requires ungluing the screen and removing the motherboard.[36] The 27 in version features an access port to upgrade memory without disassembling the display.[37] Apple also upgraded the computers' processors, using Intel's Ivy Bridge microarchitecture-based Core i5 and Core i7 microprocessors.

Video cards are now Nvidia as standard. USB 3.0 ports are now included for the first time. The 2012 iMac also features the option of a Fusion Drive which combines an SSD and a conventional HDD to create more efficient and faster storage. Apple also removed the built-in optical drive starting with this iMac generation.

On March 5, 2013, Apple quietly announced an education-only version of the iMac, with less powerful specs for a cheaper price. It includes a 3.3 GHz dual-core Intel Core i3 processor, 4 GB of memory, a 0.5 TB (1 TB = 1000 billion bytes) hard drive and Intel HD Graphics 4000, retailing for US$1,099, $200 cheaper than the base-level consumer iMac.[38]

On September 24, 2013, the 2012 iMac model was updated with 4th-generation Intel Haswell processors and Nvidia 7xx series GPU, promising up to 1.4× improvements in performance. It also has 802.11ac Wi-Fi, which is capable of reaching speeds up to 1300 Mbit/s[39] and PCIe-based flash storage, offering up to 1.5× the performance of previous-generation (Ivy Bridge) iMacs. This applies to both the Fusion Drive and pure-SSD options. These became the last iMacs to offer Target Display Mode, as the Retina line introduced the following year are incompatible with the feature due to resolution differences.

At WWDC on June 5, 2017, a refreshed model was added with Kaby Lake processors and Bluetooth 4.2 support.

A Retina Display "5K" model with a resolution of 5120 × 2880 was introduced alongside the previous year's models during a keynote on October 16, 2014. This 27-inch model was given faster Haswell processors and its two Thunderbolt ports were updated to Thunderbolt 2. Secondary storage was also upgraded to a 1 TB[59] Fusion drive as standard and video options changed over to AMD Radeon R9 M290X and M295X.

In May 2015, a separate, affordable, budget counterpart of the 5K 27-inch iMac was announced with lower specifications. That same day the late 2013 iMac lineup was completely discontinued. Later that year, a 21.5-inch "4K" model with a resolution of 4096 × 2304 was released on October 13, 2015 with older Broadwell processors, as the 27-inch counterparts were upgraded that day directly to Skylake ones. The new rechargeable and wireless peripherals were also introduced that day. In 2017 both 21.5 and 27-inch iMacs were refreshed with Kaby Lake Processors, Thunderbolt 3 (USB-C) ports, and Bluetooth 4.2. The iMacs were refreshed again in 2019 with Coffee Lake processors, upgraded graphics, and faster memory.

On August 4, 2020, Apple refreshed the 27-inch 5K iMac with Comet Lake processors, AMD RDNA architecture GPUs, the T2 security chip, a 1080p FaceTime camera, Bluetooth 5, improved speakers and microphones, and solid state drives (SSD) standard. 10 Gigabit Ethernet and nano-etched glass, similar to the Pro Display XDR, are available as upgrade options. All models include non-replaceable, soldered SSDs, while models upgraded to 4TB and 8TB include an expansion bay for a second SSD.[60] The 2019 21.5-inch versions remained available but received a minor configuration change with SSDs standard, with higher-capacity Fusion Drives as a build-to-order option, while hard disk drives are no longer available.[61] After including them for 35 years starting with the Macintosh XL in 1985, the 2020 refresh marks the end of hard disk drives in standard configuration Macs, as the 21.5-inch iMac was the only Mac still using them.[62]