Apple has updated its 4K and 5K iMac models with newer Intel Core CPUs and AMD Vega GPUs. The 4K model now comes in two variants with a choice of 8th gen. 3.6GHz quad-core Core i3 or 8th gen. 3.0GHz 6-core Core i5. Both can be configured with an optional 8th gen. 3.2GHz 6-core Core i7. The 5K model comes in three variants, with a choice of 8th gen. 3.0GHz 6-core Core i5, 8th gen. 3.1GHz 6-core Core i5, and 9th gen. 3.7GHz 6-core Core i5. The second and third variants can be configured with a 9th gen. 3.6GHz 8-core Core i9. On the GPU side, the 4K model gets a choice of Radeon...