Looking for a bare minimum GPU for 4k casual browsing

Hey all! Getting my S/O into building her own PC and I'm looking into 4K for sure, and all I'm wondering is what's the lower end GPU's (AMD or Nvidia, doesn't matter) to support 4k browsing and possible Dolphin emulation (she likes Gamecube). Also, if you guys have any advice on CPU as well, that would be awesome