Today, Apple will finally begin taking orders for newly refreshed 21- and 27-inch iMacs. The new versions don't change the basic design or add major new features, but they offer substantially faster configuration options for the CPU and GPU.

The 21.5-inch iMac now has a 6-core, eighth-generation Intel CPU option—up from a maximum of four cores before. The 27-inch now has six cores as the standard configuration, with an optional upgrade to a 3.6GHz, 9th-gen, 8-core Intel Core i9 CPU that Apple claims will double performance over the previous 27-inch iMac. The base 27-inch model has a 3GHz 6-core Intel Core i5 CPU, with intermediate configurations at 3.1GHz and 3.7GHz (both Core i5).

The big news is arguably that both sizes now offer high-end, workstation-class Vega-graphics options for the first time. Apple added a similar upgrade option to the 15-inch MacBook Pro late last year.

In this case, the 21.6-inch iMac has an option for the 20-compute-unit version of Vega with 4GB of HBM2 video memory. That's the same as the top-end 15-inch MacBook Pro option.

The 27-inch iMac can now be configured with the Radeon Pro Vega 48 with 8GB of HBM2. For reference, the much pricier iMac Pro has Vega 56 and Vega 64 options. Apple claims the Vega 48 will net a 50-percent performance improvement over the Radeon Pro 580, the previous top configuration.

Speaking of the previous top configuration, the non-Vega GPU options are the same as what was available yesterday. The only difference is that they now have an "X" affixed to the numbers in their names, per AMD branding conventions—i.e., Radeon Pro 580X instead of 580. RAM options are the same in terms of volume (up to 32GB for the 21.5-inch and 64GB for the 27-inch), but the DDR4 RAM is slightly faster now, at 2666MHz.

These changes apply to the retina iMac models. The entry-level, non-retina iMac is still available in Apple's store, but it has not been updated.

Apart from those spec bumps, the machines are essentially unchanged from their predecessors. The form factors are the same, as are the displays—both have been acclaimed and proven popular, so Apple presumably didn't see a need to upgrade those. We also got confirmation from Apple that the new iMacs do not have the T2 chip that has appeared in the iMac Pro, Mac mini, MacBook Pro, and MacBook Air.

The iMac had not seen an update since June of 2017. The new iMacs will become available in Apple's store today and will ship starting next week. The US price points remain the same, as we saw with the previous models.

Apple also announced updates for the iPad lineup earlier this week—a new iPad Air and a refreshed iPad mini, both with the new A12 processor found in the latest iPhones. Together, these two off-stage announcements seem to suggest that Apple's March 25 keynote event will focus entirely on software and services, like the company's upcoming streaming TV platform.

Update: Apple has also quietly updated the configuration options for the iMac Pro. A 256GB RAM option has been added, as well as a Radeon Pro Vega 64X GPU option. Additionally, some previously existing configure-to-order choices for the GPU, SSD, and RAM have reduced in price.

Listing image by Apple