Updated models with AMD graphics options expected in early 2017.
New iMacs Still Coming Before Holidays?
The iMac has traditionally shared an internal design with Apple's notebook computers so it's conceivable that they could see the same NVIDIA chipset revisions the current MacBooks and MacBook Pros have seen. The iMac, however, has already been using the faster 1066MHz front-side bus since its last revision in April.
The low end iMacs currently ship with ATI Radeon graphics cards with an NVIDIA GeForce 8800 GS as an upgradable option. Apple has said they would start building in Mini Display ports into all their machines from now on. Firewire's fate on the consumer machines remain unclear.