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Apple's third Apple silicon iMac gains the M4 chip alongside a range of other small but notable improvements, so how does the new machine compare to its two predecessors?

M4-iMac-Feature-Teal.jpg

The 2021 iMac was the first of its kind to feature an Apple silicon chip, replacing previous Intel-based models with 21.5- and 27-inch displays. It offered an all-new ultra-thin design, a 24-inch Retina display, a six-speaker system with force-cancelling woofers, and an array of seven two-tone color options. The 2023 model was a minor update that added the M3 chip and specification updates like Bluetooth 5.3 and Wi-Fi 6E. One year later, the latest, M4 version of the device looks like a much more substantial upgrade, offering a dramatically more powerful Neural Engine, 16GB of memory as standard, a 12-megapixel camera with Center Stage, USB-C accessories, and a nano-texture display option.

The 2021 and 2023 iMacs have now been discontinued by Apple and prices at third-party resellers are falling. As such, some customers may be weighing up whether to pick up a 2021 or 2023 iMac instead of the latest model, while some existing iMac users may be wondering if it's now time to upgrade to the M4 model.

The three Apple silicon iMac models share the overwhelming majority of their features, so should you consider buying or sticking with the first- or second-generation models to save money? This breakdown also serves as a way to see all the differences that the 2024 iMac brings to the table.

iMac (2021)iMac (2023)iMac (2024)
M1 chip (made with TSMC's 5nm (N5) process)M3 chip (made with TSMC's 3nm (N3) process)M4 chip (made with TSMC's enhanced 3nm (N3E) process)
3.20 GHz maximum CPU clock speed4.05 GHz maximum CPU clock speed4.30 GHz maximum CPU clock speed
16 billion transistors25 billion transistors28 billion transistors
8-core CPU8- or 10-core CPU8- or 10-core CPU
7- or 8-core GPU8- or 10-core GPU8- or 10-core GPU
Updated GPU architectureUpdated GPU architecture with improved efficiency
Dynamic CachingDynamic Caching
Hardware-accelerated ray tracingHardware-accelerated ray tracing
Hardware-accelerated mesh shadingHardware-accelerated mesh shading
Video decode engineHigher-bandwidth video decode engineHigher-bandwidth video decode engine
Hardware-accelerated H.264 and HEVCHardware-accelerated H.264, HEVC, ProRes, and ProRes RAWHardware-accelerated H.264, HEVC, ProRes, and ProRes RAW
ProRes encode and decode engineProRes encode and decode engine
Support for AV1 decodeSupport for AV1 decode
LPDDR4X memory LPDDR5 memoryLPDDR5X memory
68.25GB/s memory bandwidth100GB/s memory bandwidth120GB/s memory bandwidth
8GB or 16GB unified memory8GB, 16GB, or 24GB unified memory16GB, 24GB, or 32GB unified memory
16-core Neural Engine, 11 trillion operations per second16-core Neural Engine, 18 trillion operations per second16-core Neural Engine, 38 trillion operations per second
1080p FaceTime HD camera1080p FaceTime HD camera12-megapixel camera
Center Stage with support for Desk View
Image signal processor (ISP)"New" image signal processor (ISP)"New" image signal processor (ISP)
Nano-texture display option
Dedicated display engine
Support for up to one external displaySupport for up to one external displaySupport for up to two external displays
3.5mm headphone jack3.5mm headphone jack with support for high-impedance headphones3.5mm headphone jack with support for high-impedance headphones
Up to two Thunderbolt/USB 4 ports and two USB 3 portsUp to two Thunderbolt/USB 4 ports and two USB 3 portsUp to four Thunderbolt 4 ports
Wi-Fi 6Wi-Fi 6EWi-Fi 6E
Bluetooth 5.0Bluetooth 5.3Bluetooth 5.3
Available in Silver, Green, Yellow, Orange, Pink, Purple, and BlueAvailable in Silver, Green, Yellow, Orange, Pink, Purple, and BlueAvailable in Silver, as well as new shades of Green, Yellow, Orange, Pink, Purple, and Blue
Magic Keyboard and Magic Mouse/Magic Trackpad with Lightning portMagic Keyboard and Magic Mouse/Magic Trackpad with Lightning portMagic Keyboard and Magic Mouse/Magic Trackpad with USB-C port


The 2024 iMac with the M4 chip marks a much more substantial upgrade compared to the 2021 and 2023 models. Key improvements such as the significantly more powerful Neural Engine for AI and machine learning tasks, increased standard memory of 16GB, 12-megapixel camera with Center Stage, and support for USB-C accessories make it an appealing choice for future-proofing. Performance-wise, it delivers a meaningful boost, especially for those upgrading from the M1 iMac or older Intel-based iMacs, where Apple claims up to 6x faster performance than the most popular Intel iMac.

For M1 iMac users, the M4 model could be worth considering if they require enhanced performance or a richer set of features, such as hardware-accelerated ray tracing, nano-texture display option, or simply a better webcam. However, M3 iMac users may find fewer incentives to upgrade, as the performance gap between M3 and M4 is good but not as significant in daily use unless the system is pushed to the limit. The M3 iMac is built to handle demanding tasks and will remain relevant for several more years, but M1 iMac users may want to begin considering an upgrade.

Starting at $1,299, the new iMac remains a solid investment for those looking for a device with longevity, a robust array of features, and meaningful upgrades over the original M1 model or older Intel machines. However, if you have basic needs and find a discounted 2023 iMac, this could still offer good value, though the M4 will better me... Click here to read rest of article

Article Link: M1 vs. M3 vs. M4 iMac Buyer's Guide: 25+ Upgrades Compared
 
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Reactions: SFjohn
It's almost SUATMM (Shut UP and Take My Money) time... I can smell M4 Max right on the horizon... come on, come on...
 
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Reactions: TVreporter
Our M1 model is literally just a terminal to upload youtube videos overnight or check emails, so not sure if upgrading is needed. That green one is beautiful though
 
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16GB RAM minimum finally! Took them 10 years to make the bump from 8GB to 16Gb RAM.

I think it was 2020 when SSD minimum was bumped to 256GB. So we should see 512GB minimum in 2030?
 
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Reactions: UnbreakableAlex
looking forward to this comparison for the M1 Pro vs M4 Pro when it's announced!
Will be interesting to see what the specs/pricing of the M4 Pro actually are - the 10 core M4 seems to have stolen a lot of its thunder.

I have a slight suspicion that the M4 Pro will be the "new Max", the M4 Max the "new Ultra" and the new "Ultra" strictly for people in the "Mac Pro" price bracket...
 
16GB RAM minimum finally! Took them 10 years to make the bump from 8GB to 16Gb RAM.

I think it was 2020 when SSD minimum was bumped to 256GB. So we should see 512GB minimum in 2030?
You may have found the Apple secret. The doubling time of a quantity that increases steadily by 7% per year is 10 years (70/7 = 10). So that means their "minimum spec bump" timeline is 10 years. It probably works out about right for CPU capabilities too. A 2014 Mac probably has about half the single-core performance of an M4.

Of course, the actual silicon advances way faster than 7% per year, but in order to make it economical and sell machines in the $500-1000 range with a hefty profit margin, they limit the base model to this 7% per year figure.

Those who want their hardware to advance faster than 7% per year can pay a huge premium (mostly profit) for higher specs.
 
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Reactions: Agile55
Will be interesting to see what the specs/pricing of the M4 Pro actually are - the 10 core M4 seems to have stolen a lot of its thunder.

I have a slight suspicion that the M4 Pro will be the "new Max", the M4 Max the "new Ultra" and the new "Ultra" strictly for people in the "Mac Pro" price bracket...
Making the M4 Pro the "new Max" would be a huge downgrade for existing M3 Max customers. M4 Pro will have way fewer GPU cores and about half the memory bandwidth of the top-spec M3 Max. There's no reason they would do that. Profit margins are huge for the Max chips - they are financially motivated to keep drumming out a new one every year, but it absolutely must be faster than last year's. If it's slower and has fewer cores and less memory bandwidth, literally nobody will buy it, even if the price is chopped down a ton.
 
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Reactions: Chuckeee
The more expensive M4 models support two external displays.

I'm assuming this means internal display + two external displays. If this comes to MacBook Air M4 then I no longer need a MacBook Pro as my main business laptop.

I don't think we're getting Airs this week, but my decision is made on my next Apple Silicon Laptop.
 
Say I went with the base model, what's the best external hard drive to get to sync my Photos library? It's too large to fit on the base 256GB internal hard drive, and I'm thinking of saving the cost of the Apple-premium SSD upgrade. Would Thunderbolt 4 be a help here? Are there any external SSDs that utilize it?
 
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