Apple launches updated iMac Pro with 256GB RAM and Radeon Pro Vega 64X Graphics add-on

Apple has quietly released an update to its iMac Pro, adding a new 256GB RAM and Radeon Pro Vega 64X graphics option to the machine.
The update to the iMac Pro follows moments after Apple refreshed its iMac range, introducing a new 21.5-inch iMac featuring 8th-generation Intel CPUs in quad-core and six-core SKUs, and a refreshed 27-inch iMac using 9th-generation Intel CPUs, with 6-core and 8-core configurations, delivering up to 2x the performance of the previous generation iMac.
Bumping your machine to 256GB of 2,666MHz DDR4 ECC memory adds an additional $5,200 to the cost of the iMac Pro itself. – The Radeon Pro Vega 64X graphics add-on is priced at $700.
Customers wanting to add either 256GB RAM or Radeon Pro Vega 64X Graphics must do so when ordering the machines through Apple.com.