The first iMac with Apple Silicon was released in 2021 with the M1 chip and a new 24″ form factor with multiple colors, replacing the 21.5″ and 27″ iMacs. Two years later, Apple has updated the 24″ iMac with the M3 chip.
Let’s break down all the differences, and then talk about who should upgrade, and who should not.
Exterior
The outside of the iMac hasn’t changed at all. There is still just the one 24″ size with 4.5K Retina display, and it comes in the same 7 color options. And even the accessories like the Mouse and Keyboard still come with Lightning connectors instead of USB-C.
CPU
So let’s head inside, and the biggest difference is of course the M3 chip, which is built on the new 3nm technology compared to the M1’s 5nm process. The CPU is 8 cores on both M1 and M3, but Geekbench reveals the single-core performance is 30-36% higher on M3, while the multi-core performance is 40-45% higher. It’s a 2 generation leap from M1 to M3, and the clock speed is faster as well, so this isn’t surprising.
GPU
On the graphics side, the base $1300 iMac used to have an M1 chip with 7 GPU cores, while now it has the M3 with 8 GPU cores. The higher tier $1500 iMac with M1 had an 8-core GPU, and with M3 it now has 10 cores. At this time, it’s a bit hard to find GPU benchmarks for all configurations, though Apple states that the M3 GPU is up to 65% faster than M1.
That isn’t too surprising, since 10 GPU cores is already 25-43% more cores than M1, and being two generations newer and having improved GPU tech like dynamic caching, hardware-accelerated ray tracing, and mesh shading, the per core performance should be higher as well.
Neural Engine
The 16-core neural engine still persists from M1 to M3, although performance has improved by about 60% according to Apple. Unless you have a known machine learning workload, this probably isn’t a big deal for you.
Memory
A disappointment with the M3 iMac is that the starting memory is still a paltry 8GB with all stock configurations, same as the M1. However, while the M1 topped out at 16GB, you can go all the way up to 24GB with the M3, paying $200 for each 8GB increment.
Unified memory bandwidth is also faster on the M3 chip at 100GB/s compared to the 68.25GB/s of the M1 chip. Most iMac users probably don’t need to be concerned about this number.
Media Engine
The media engine of the M3 has seen some improvements compared to M1, adding hardware accelerated encoding and decoding for ProRes and ProRes RAW formats, so ProRes workflows could be much faster. There’s also AV1 decoding, which helps with playing back higher-quality streaming video, but since the iMac is a desktop, the benefits of this aren’t as high as a laptop where battery life could be improved by having this on hardware.
And although the M3 chip launch didn’t specifically mention it, the M2 chip had a “new image signal processor (ISP)” that delivers better image noise reduction, so I’d assume that’s still on M3. I honestly don’t know if that makes any significant difference, but hey, it’s there.
Audio
On the audio side, a hidden benefit of the 3.5mm headphone jack on the M3 iMac is that it now supports high-impedance headphones, a feature missing from the M1 iMac from 2021.
Wi-Fi and Bluetooth
Going to wireless connectivity, the M3 iMac has Wi-Fi 6E compared to the M1 iMac’s Wi-Fi 6. Wi-Fi 6E is faster than Wi-Fi 6, but the biggest benefit is being able to use the 6 GHz wireless band that is less crowded compared to 2.4 and 5 GHz.
Bluetooth has also been upgraded from 5.0 to 5.3 on the M3 iMac. This isn’t a huge deal, but there are some interesting improvements like Low Energy Audio.
Who Should Upgrade
And that’s it for the differences between the M1 and M3 iMacs. All told, the main difference is the M3 chip that offers faster performance, and that is essentially the ONE reason you would upgrade. So… should you upgrade?
Well, first of all, if you don’t have an iMac and like the all-in-one form factor and design, then getting the M3 iMac over a used M1 is not a bad idea. 40% extra CPU and 60% extra GPU performance is significant, and probably worth the cost difference.
But I think for the majority of M1 iMac owners, there is no need to upgrade. There’s no new design or capabilities, and for most everyday tasks, you probably won’t even notice any difference. The M1 chip is still very capable, so if you aren’t pushing the limits, stick with it.
However, if you really like the iMac form factor, and you just want the best performance you can get while still having an all-in-one Mac computer, then it could be worth the trouble of upgrading to the M3 iMac. CPU and GPU performance on the M3 is a big improvement over M1, so if you were just hitting the limit of M1 being good enough, then the M3 chip could be perfect. If you want even more performance though, you should consider the Pro or Max level chips, and unfortunately that means the iMac isn’t for you.
That’s because Apple has really given us no other choice. They stated pretty clearly that they see the 24″ iMac as the perfect “middle-ground” replacement for both the 21.5″ and 27″ iMacs, which means we probably won’t be getting a larger or more powerful iMac anytime soon. This personally makes me sad, as I’ve owned many iMacs in the past, and I’m sure like many others, I’d been hoping they would continue to serve the power user all-in-one market with a larger iMac.
