M1 vs. M3 vs. M4 iMac Buyer's Guide: 25+ Upgrades Compared
by Hartley Charlton · MacRumorsApple'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?
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 speed | 4.05 GHz maximum CPU clock speed | 4.30 GHz maximum CPU clock speed |
| 16 billion transistors | 25 billion transistors | 28 billion transistors |
| 8-core CPU | 8- or 10-core CPU | 8- or 10-core CPU |
| 7- or 8-core GPU | 8- or 10-core GPU | 8- or 10-core GPU |
| Updated GPU architecture | Updated GPU architecture with improved efficiency | |
| Dynamic Caching | Dynamic Caching | |
| Hardware-accelerated ray tracing | Hardware-accelerated ray tracing | |
| Hardware-accelerated mesh shading | Hardware-accelerated mesh shading | |
| Video decode engine | Higher-bandwidth video decode engine | Higher-bandwidth video decode engine |
| Hardware-accelerated H.264 and HEVC | Hardware-accelerated H.264, HEVC, ProRes, and ProRes RAW | Hardware-accelerated H.264, HEVC, ProRes, and ProRes RAW |
| ProRes encode and decode engine | ProRes encode and decode engine | |
| Support for AV1 decode | Support for AV1 decode | |
| LPDDR4X memory | LPDDR5 memory | LPDDR5X memory |
| 68.25GB/s memory bandwidth | 100GB/s memory bandwidth | 120GB/s memory bandwidth |
| 8GB or 16GB unified memory | 8GB, 16GB, or 24GB unified memory | 16GB, 24GB, or 32GB unified memory |
| 16-core Neural Engine, 11 trillion operations per second | 16-core Neural Engine, 18 trillion operations per second | 16-core Neural Engine, 38 trillion operations per second |
| 1080p FaceTime HD camera | 1080p FaceTime HD camera | 12-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 | ||
| 3.5mm headphone jack | 3.5mm headphone jack with support for high-impedance headphones | 3.5mm headphone jack with support for high-impedance headphones |
| Up to two Thunderbolt/USB 4 ports and two USB 3 ports | Up to two Thunderbolt/USB 4 ports and two USB 3 ports | Up to four Thunderbolt 4 ports |
| Wi-Fi 6 | Wi-Fi 6E | Wi-Fi 6E |
| Bluetooth 5.0 | Bluetooth 5.3 | Bluetooth 5.3 |
| Available in Silver, Green, Yellow, Orange, Pink, Purple, and Blue | Available in Silver, Green, Yellow, Orange, Pink, Purple, and Blue | Available in Silver, as well as new shades of Green, Yellow, Orange, Pink, Purple, and Blue |
| Magic Keyboard and Magic Mouse/Magic Trackpad with Lightning port | Magic Keyboard and Magic Mouse/Magic Trackpad with Lightning port | Magic 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 meet the needs of those seeking higher performance, better features, and a more forward-looking setup.