Apple announced updated 21.5-inch and 27-inch iMacs last week. Let’s take a quick look at the performance of the new iMacs using Geekbench 4 results from the Geekbench Browser.

For those unfamiliar with Geekbench 4, it is our cross-platform CPU and GPU benchmark. Higher scores are better, with double the score indicating double the performance.

iMac (21.5-inch) Performance

Single-Core Performance

Multi-Core Performance

There are currently no results for the new 21.5-inch iMac with an i7 processor. I expect its performance will be comparable to the Mac mini with an i7 processor as their processors have the same number of cores and frequencies.

For the new 21.5-inch iMac with i3 and i5 processors, single-core performance is up 5-10%, and multi-core performance is up 10-50%. Since the processor architecture is effectively unchanged between the 7th generation and the 8th generation Intel Core processors, most of the increase is due to higher frequencies and higher core counts.

iMac (27-inch) Performance

Single-Core Performance

Multi-Core Performance

For the new 27-inch iMac, single-core performance is up 6-11%. Multi-core performance is up 43-49% for the 6-core models, and up 66% for the 8-core models. Again, the increase is due to higher frequencies and core counts, not to any architectural improvements.

iMac, iMac Pro Performance

Single-Core Performance

Multi-Core Performance

The new 6- and 8-core iMac is even competitive with the 8- and 10-core iMac Pro. For example, the 8-core iMac has 16% higher single-core performance and 10% lower multi-core performance than the 10-core iMac Pro.

Conclusion

For users with multi-core aware applications, the new iMacs provide a significant boost in multi-core performance, with the new 8-core 27-inch iMac providing a compelling alternative to the 8- and 10-core iMac Pro. The single-core performance is great as well, with the new iMacs occupying the top spots in our Mac Benchmark chart, but I don’t think the increase is enough to justify upgrading from a 2017 iMac.