You'll pay an extra $200 for the 8-core GPU version. 24-inch iMac (2021): The SoC comes with an 8-core CPU with four performance cores and four efficiency cores, 7- or 8-core GPU, and 16-core Neural Engine.There's one choice of SoC on the models below - the Apple M1. Other Apple silicon models come with one choice option, the M1, or, in the case of the 14-inch MacBook Pro (2021), the M1 Pro. To date, only the 16-inch MacBook Pro (2021) offers a choice of Apple silicon (M1 Pro or M1 Max). Instead, you can choose the Apple silicon version (when possible), then select the RAM and storage. You can no longer, for example, select the computer's central processing unit or CPU.
With the shift toward Apple silicon, there are different choices one can make on the consumer side.