what you really need is RAM, lots of it! I'll recommend at least 32 GB for a decent system. The next thing you need are high clocked cores. I think the i7 7700 will work well. I would take the "k" version which clocks at 4,2GHz and only costs a bit more. If you have money to spend, go with a 6 or 8 core cpu.
Depending on what you are going to do in After Effects, the graphic card is more or less useful. I'm doing a lot motion design with Illustrator files and After Effects hardly use my graphic card. I only have a GTX 760 and it's most of the time in idle.
I also recommend a SSD or even M.2 HDD for diskcache.
Thank you very much!
I've checked both i7 7700K and 6850K. 7700K has 4 cores and its speed is Ghz 4.2 and the 6850K has 6 cores but its speed is only Ghz 3.6. Which one is more useful (or any other CPU you recommend of)?
my last AfterEffects-VR-360°-Workstationbuild has an i7 6800K (6x 3.4 GHz) and the motion graphic man says, it worked like charm. So I recommend the 6-core CPU. Go with the 6850K if you can. Overclocking is also an option, but I would try the performance with stock clocks at first.
In a couple of months, (maybe only weeks), Intel will release the new i9 series. There are 10, 12, and also 18 cores CPUs (18 core will be at 2000 bucks). If you have the time you can wait so see if prices drop for those i7 6 and 8 cores, or you go with a new i9.
Great! thanks a lot!