The "Kaby Lake" chip is the most commonly used i7 processor and is also available in i5 and i3 variations. The i7 is the most powerful version which is why we use that in our editing systems. The Broadwell-E and Xeon processors are faster and have more "cores". They can also handle more "add-in" boards.
When editing 4K footage the more power the better, so for most people we would recommend that they buy a Broadwell-E or Xeon system for editing 4K. This does not mean you cannot edit 4K on the Kaby Lake system. With most programs we can edit 1-2 layers of 4K video using the Kaby Lake. However, for 4K the more power the better so if you have the budget we would suggest an 8 core Broadwell-E or a dual Xeon system.
♦ In Grass Valley EDIUS we can manage two streams of video using footage from the GH4 camera but it struggles to playback 4K MOV files from the Blackmagic 4K Production camera. The big advantage of using this system with EDIUS is that you also get Intel Quick Sync which means this system can make 4K H.264 files in realtime. On higher spec machines playback will be better but encoding take longer.
♦ In Adobe Premiere Pro CC we have very similar performance with both kinds of footage.
♦ The recommended Avid Media Composer 4K system is a dual 10 core Xeon. This system is less powerful than this recommend system but can cope with 4K from various formats with Avid, although you may need to transcode or work at a lower resolution
♦ Magix Vegas can edit 4K with this system but you would need to drop the resolution for reasonable playback.
♦ Blackmagic DaVinci Resolve can playback Blackmagic ProRes MOV files on this computer but cannot handle GH4 files very well. You would need to choose a graphic card with at least 4GB RAM for 4K playback.
Should I buy a Kaby Lake system for 4K?
For 4K editing you really want as much power as possible and the Kaby Lake processor is the least powerful of our 3 desktop computers. However, it is still very powerful and with programs like EDIUS and Premiere Pro can edit 4K very well.