What are you editing?
The requirements for 4k video are MUCH greater than regular Hi Def
Fast i7 with multi-threading capability'
16 Gig ram as a minimum
256Gig SSD for Windows and programs
2nd drive for video and work files
NVidia graphics adapter with minimum 1Gig video ram
Moved to the Hardware Forum.
like $750-$850, give or take
I think you may have to spend nearly double that.