Apple may actually bring updated iMacs running Intel’s 8th Gen Coffeelake Processors alongside the iMac Pro in December or in early 2018. We just caught several iMacs running on the 8th Gen i7-8700 & i7-8700K Processors on Geekbench. The scores are as expected crashing the board on both Single & Multi-threaded side. These seem to be the 27 inch 5K models so, Apple is probably bringing the 2018 Models of the 27 inch iMac. Have a look at the scores from both the 8700 & 8700K models…
iMac Running Coffeelake i7-8700
iMac Running Coffeelake i7-8700K
Currently the 7th Gen 4-core i7-7700K ships with the i7 models of the 27 inch 5K iMac so, the new 6-core i7-8700K will definitely bring huge improvements over the last gen iMacs. And I know the 18-core iMac Pro is also coming out next month. But, not everyone can afford that & maybe many people cannot even utilize that super-multicore power. So, the 6-core iMac Pro will be a great option for those people.
The pricing may or may not bump up but, with the base components, the 5K 27 inch iMac with the i7-7700K & AMD RX580 Graphics starts at 2499 for 8GB RAM & if you bump that up to 16 Gigs, it’ll cost you 2699. So, even more price increase isn’t really an ideal thing to do. It’s better if Apple at least sticks the the old prices.