Apple renewed its iMac series of computers with the new 21.5 and 27-inch models. In addition to the new Intel processors, the improvement came in the form of better screen, which now have a 4K (21.5-inch) and 5K (27-inch) resolution.

There are now three 21.5-inch iMac models – of which only one received a 4K display. The first and second model come with a dual-core Core i5 processor with speed of 1.6 (Boost 2.7 GHz) and 2.8 (Boost 3.3 GHz) GHz and Intel HD 6000 and HD 6200 graphics. Resolution of their screens are 1,920 x 1,080 pixels.
The most powerful 4K model has a quad-core i5 processor speed of 3.1 GHz (3.6 GHz Boost) and Intel HD 6200 graphics. Available for customers is also the Core i7 processor speed of 3.3 GHz (3.8 GHz Boost). Screen resolution is 4,096 x 2,304 pixels. Regardless of the model, Apple has all the 21.5-inch iMacs equipped with 8 GB of LPDDR3 memory with speed of 1867 MHz, which can subsequently be increased to a maximum of 16 GB.
Also all three models come with a hard drive capacity of 1TB, but due to the wishes of customers there are also available the Fusion Drive with one and two terabytes and 256-gigabyte SSD. The first, weakest model costs 1,099 US dollars, second 1,299  and the most powerful, 4K model 1,499 US dollars.
Apple also introduced three new 27-inch iMacs, but for them there is only one screen available- 5K resolution, ie, the screen with resolution of 5,120 x 2,880 pixels. For the 27-inch iMac Apple has prepared three quad-core Core i5 processors and one quad-core i7 processor.
Speeds of Core i5 processor this time range from 3.2 (Boost 3.6 GHz) to 3.3 GHz (3.9 GHz Boost), while the Core i7 processor has the speed of 4.0 GHz (4.2 GHz Boost). Basic amount of memory in 27-inch iMac is 8 GB, where the respective model subsequently can be upgraded to a maximum of 32 GB of RAM.
The offer of hard drives is also a little bit changed, and initial setup of hard disk is made out of drives with a capacity of one and two terabytes. As for additional equipment,  Apple has prepared Fusion Drive with 3 TB and SSD disk with capacity of 256 and 512 GB and one SSD with 1TB.
In terms of graphics 27-inch iMac is based on AMD’s solutions – ie. the Radeon R9 M380, Radeon R9 M390 and Radeon R9 M395 video cards with 2 GB of GDDR5 VRAM and M395X Radeon video card with 4GB of GDDR5 VRAM.
Bigger screen, better hardware also bring higher prices that range from 1799 to 2299 US dollars. More detailed specifications of the new 21.5-inch and 27-inch iMacs you can find at Apple’s official website.