21.5-inch 3.0GHz 6-core Core i5 iMac (2019) review: New all-in-one stands out in multi-core performance

Apple seems to have settled into a groove with a two-year update cycle for the iMac. The latest iteration of the company’s all-in-one desktop computer comes nearly two years after the previous release—and the 2017 iMac came two years after its predecessor. Updates to the processor, RAM, and graphics card are in the spotlight for Apple’s newest iMac; the rest of the machine remains unchanged.

This review evaluates the 21.5-inch iMac with a 3.0GHz Core i5 processor. The standard configuration of this iMac is priced at $1,499 but the model reviewed here has the graphics card upgraded to the Radeon Pro Vega 20, which adds $350 to the price.

Faster CPU, graphics, and RAM

Two of the 2019 21.5-inch iMacs are built around Intel’s eighth-generation Core processor, while the entry-level $1,099 iMac still uses a seventh-generation CPU. Our review unit has a 3.0GHz Core i5 processor with six cores and Turbo Boost support up to 4.1GHz. This is actually the first 21.5-inch iMac model to sport a six-core CPU. Previous 21.5-inch iMacs had quad-core processors, and the model a step below our review unit, the new $1,299 21.5-inch iMac, is still a quad-core computer. The two additional processing cores will benefit anyone who works in apps that use multi-core processing—usually creative professionals that use high-end video, audio, and imaging software, but many other professional-level apps, as well.

If you’re one of those pros eying this iMac, you’re probably interested in the graphics card upgrade from the standard 4GB Radeon Pro 560X to the 4GB Radeon Pro Vega 20. As for external display support, the iMac can handle a single 5K display, or a two 4K displays.

Apple decided to use faster RAM in the 2019 iMac, too. Apple now uses 2666MHz DDR4 memory, a small increase in speed from the 2400MHz DDR4 memory used before. The standard RAM configuration is 8GB (our review unit is configured this way). The RAM in the 21.5-inch models is still not user accessible, unfortunately. If you want to add more RAM later, you need to bring in the iMac to an authorized service provider. Or you can upgrade to 16GB ($200) or 32GB ($600) at the time of purchase. The 27-inch iMac has user-accessible RAM.

Boosted iMac speed

We ran several benchmark tests to gauge the speed of the 21.5-inch 3.0GHz 6-core Core i5 iMac with 8GB of 2666MHz DDR4 RAM, and 4GB Radeon Pro Vega 20 graphics. We compared the results primarily to the 2017 model with 3.4GHz quad-core Core i5 processor with 2400MHz DDR4 memory and 4GB Radeon Pro 560 graphics, which sold for $1,499. When possible, we included benchmarks from other Macs for reference.

Geekbench 4 Single-Core test

imac 2019 geekbench single core IDG

Results are scores. Longer bars are better. Click to enlarge.

In single-core testing, the new iMac provides modest gains over its 2017 predecessor. The 2019 21.5-inch 3.0GHz Core i5 iMac had a 7 percent boost over the 2017 3.4GHz Core i5 iMac. If you compare the 2019 iMac to the 2015 3.3GHz Core i7 iMac, the boost is a little more impressive: we saw a 20 percent performance increase. 

We also took a look at how the single-core performance of the new iMac compares to the current 3.6GHz Core i3 Mac mini ($799). The iMac bests the Mac mini by 12 percent, which isn’t that surprising when you consider that the iMac’s faster Core i5 is up against the Mac mini’s slower Core i3 processor.