What are all the differences between the "2021 M1" iMac models? Which one is best for me?

The "2021 M1" iMac models have been discontinued. However, this Q&A has been updated subsequently and can be quite useful for anyone buying or selling one on the used market.

There are two distinct Apple Silicon-powered "2021 M1" iMac models -- the iMac 24-Inch "M1" 8-Core CPU/7-Core GPU/2 USB-C Shaped Ports (2021) and iMac 24-Inch "M1" 8-Core CPU/8-Core GPU/4 USB-C Shaped Ports (2021).

With a quick glance at these iMac models, they look practically identical, but there are notable differences that are important to understand in order to determine which is your best choice.

Photo Credit: Apple, Inc. (iMac 2021 M1 Models)

External Differences

Both "2021 M1" iMac models use a wafer thin, all aluminum design with flat sides and a light gray frame around the display and a small "chin" underneath. By default, these iMac models are mounted on an aluminum stand and are not VESA compliant, but they can be configured with a VESA mount option instead of the stand at the time of purchase at no extra charge.

Despite their formal designation as packing "24-Inch" 4.5K Retina displays, the "2021 M1" iMac models actually have a 23.5-Inch LED-backlit widescreen TFT active matrix "Retina 4.5K" display with a native resolution of 4480x2520 at 218 ppi with "support for 1 billion colors," True Tone technology, wide color (P3), and brightness of 500 nits.

Both models also have a good quality 1080p FaceTime HD camera, three-mic array, and six-speaker system for video conferencing.

Connectivity is the major point of external differentiation between the two models. Both have a 3.5-mm headphone jack conveniently located on the left side of the display -- these iMac models are so thin that it wouldn't even be possible to plug in a headphone jack on the back -- as well as 802.11ax wireless and Bluetooth 5.0.

Photo Credit: Apple, Inc. (iMac 2021 M1 Side & Headphone Jack)

However, the entry-level iMac 24-Inch "M1" 8-Core CPU/7-Core GPU/2 USB-C Shaped Ports (2021) has two USB-C shaped Thunderbolt / USB 4 ports whereas the higher-end iMac 24-Inch "M1" 8-Core CPU/8-Core GPU/4 USB-C Shaped Ports (2021) has four USB-C shaped ports, but two of the ports support Thunderbolt 4 / USB 4 and the other two support the slower USB 3 standard.

The higher-end model also is bundled with a power supply that includes a Gigabit Ethernet port whereas the entry-level model's power supply lacks a Gigabit Ethernet port by default, but can be upgraded to the same power supply as the higher-end model at the time of initial purchase for an extra US$30.

Color Differences

The "2021 M1" iMac models are offered in seven color options -- blue, green, pink, silver, yellow, orange, and purple. The colors are dark on the back and sides of each system and a lighter shade of the same color on the front below the light gray bezel that wraps around the display.

Photo Credit: Apple, Inc. (iMac 2021 M1 Color Options)

However, not all models are offered in all colors. The entry-level model only is provided in blue, green, pink, and silver, whereas the higher-end model is available in the same colors as the entry-level model and adds yellow, orange, and purple options.

Included Accessory Differences

The "2021 M1" iMac models are bundled with different color-matched input accessories.

By default, both models shipped with a wireless "Magic Mouse" with multi-touch surface support, but the entry-level model is equipped with a small aluminum wireless "Magic Keyboard" (A2450, EMC 3619) without "Touch ID" or a numeric keypad. The higher-end model has a small aluminum wireless "Magic Keyboard with Touch ID" (A2449, EMC 3579), but still without a numeric keypad.

Photo Credit: Apple, Inc. (Magic Keyboard with Touch ID and Numeric Keypad)

At the time of system purchase, the entry-level iMac could be upgraded to the same "Touch ID" equipped keyboard as its higher-end sibling for an extra US$50. Either model could be upgraded further to a "Magic Keyboard with Touch ID and Numeric Keypad" (A2520, EMC 3957) for an additional US$80 for the entry-level model and an additional US$30 for the higher-end model.

Either model additionally could be upgraded at the time of purchase to swap out the Magic Mouse for a Magic Trackpad (which provides multi-touch input and Force Touch support) for an extra US$50 or both a Magic Mouse and a Magic Trackpad for an additional US$129.

Identification Differences

At the time of its introduction, there was no mistaking the "2021 M1" iMac models for earlier iMacs, but they are nearly identical in appearance to subsequent models, so more specific details are helpful.

When the "2021 M1" iMac models were first announced, there was a great deal of confusion regarding the specific identifiers for these models because random people were guessing incorrectly with partial information. As we have done so for other Macs for more than two decades now, EveryMac.com has hand documented these identifiers directly from the hardware itself to ensure accuracy.

Model Numbers commonly are shared by later models, but they actually are unique for this line. The entry-level iMac 24-Inch "M1" 8-Core CPU/7-Core GPU/2 USB-C Shaped Ports (2021) uses the A2439 model number and the higher-end iMac 24-Inch "M1" 8-Core CPU/8-Core GPU/4 USB-C Shaped Ports (2021) uses the A2438 model number.

Other identifiers commonly are better for more specific identification, though. In software, the Model Identifier is sufficiently unique for just about all purposes. Externally, the EMC Number is best as it always is less likely to be shared by future models using the same case type, although like the Model Number, it is inconveniently located on the underside of the stand.

These identifiers for the "2021 M1" iMac models are as follows:

2021 24" iMac	Subfamily	Model ID	EMC No.
"M1" 7-Core GPU	M1 2021	iMac21,2	3664
"M1" 8-Core CPU	M1 2021	iMac21,1	3663

Additionally, EveryMac.com's Ultimate Mac Lookup feature can uniquely identify the "2021 M1" iMac models by their serial numbers.

Internal Differences

The "2021 M1" iMac models are practically the same internally, but there are a couple of potentially notable differences.

Both models are powered by a 3.2 GHz Apple M1 processor (SoC) with eight cores (4 performance cores, 4 efficiency cores) and a 16-core Neural Engine. However, the entry-level model has a 7-core GPU and the higher-end model has an 8-core GPU. In many tasks, this makes no difference in overall performance, but third-party tests show that the higher-end graphics processor is on average around 9% faster in graphics benchmarks and on average around 12% faster in some games.

Both models have "unified" onboard memory and SSD storage that cannot be upgraded at all after the initial system purchase.

By default, both models are configured with 8 GB of memory, which can be upgraded to 16 GB of memory at the time of system purchase for an extra US$200. The entry-level model is equipped with 256 GB of storage and the higher-end model is equipped with 256 GB or 512 GB of storage. Both models also can be custom configured with up to 2 TB of storage at the time of system purchase at additional cost.

"2021 M1" iMac Comparison Chart

The major differences between the "2021 M1" iMac models -- connectivity, color options, keyboards, graphics, storage, and more -- are summarized below:

	2 Ports/7 GPU	4 Ports/8 GPU
Thunderbolt:	2 (USB-C)	2 (USB-C)
USB 3:	None	2 (USB-C)
Gigabit Ethernet:	None*	Yes
Color Options:	Blue Green Pink Silver	Blue Green Pink Silver Yellow Orange Purple
Std. Keyboard:	No Touch ID	Touch ID
Std. RAM:	8 GB	8 GB
Max. RAM:	16 GB**	16 GB**
Std. Storage:	256 GB	256 GB, 512 GB
Max Storage:	2 TB†	2 TB†
Integrated GPU:	7-Cores	8-Cores
Model Number:	A2439	A2438
Model ID:	iMac21,2	iMac21,1
EMC Number:	3664	3663
Original Price (US):	US$1299	US$1499, US$1699
Original Price (CA):	C$1599	C$1849, C$2099
Original Price (UK):	£1249	£1449, £1649
Original Price (AU):	A$1899	A$2199, A$2499
Original Price (SG):	S$1,849	S$2,149, S$2,449

* Gigabit Ethernet is provided via the power supply. The entry-level model could be upgraded to include the same Gigabit-equipped power supply as the higher-end model for an extra US$30.

** At the time of purchase, either model could be upgraded to include 16 GB of RAM for an extra US$200. RAM cannot be upgraded subsequently.

† Both models could be custom configured with up to 2 TB of storage at the time of system purchase at additional cost. Storage cannot be upgraded subsequently.

So, which one should I buy? Which one is really best for me?

In a sure sign that Apple has transitioned from being less of a tech company and to more of a fashion brand, the two "2021 M1" iMac models are the same overall speed and differentiated more by color and features than performance. Want an iMac that is yellow, orange, or purple? Prices have changed now on the used market, but it originally would cost you an extra US$200.

Ignoring subsequent iMac models and that value may have shifted somewhat on the used market, if overall performance for the price is your top priority, the entry-level iMac was your best bet. Only you could decide if the extra US$200 for the higher-end model was worth it to you, but in addition to the (1) yellow, orange, and purple color options, the higher-end model offers (2) two relatively slow USB-C shaped USB 3 ports, (3) Gigabit Ethernet via the power adapter, (4) a keyboard with Touch ID capability, and (5) a modestly faster graphics processor.

Objectively, if graphics performance is important to you, the higher-end model provides about 9% more graphics performance in some tasks for 15% or so more cost. This is not a great value, but it represents a decent enough one and the higher-end model is worth considering for this upgrade alone.

Because they are slower (and it always is possible to add a hub later), the extra USB-C ports are unlikely to be that important to most users. However, if you want both Gigabit Ethernet and a keyboard with Touch ID, adding these items to the lower-end model costs an extra US$30 and an extra US$50, respectively, and at that point, you likely would be best served by the higher-end model. If you don't need Gigabit Ethernet or Touch ID, you might as well save the US$200, or better yet, put the US$200 toward 16 GB of RAM in the entry-level model to boost its performance and likely extend its usable life, as well. You cannot upgrade the RAM after purchase.

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