wanting to upgrade 4 year old desktop to Mojave

Hey there, I want to upgrade my 4 year desktop to the last mac OS

My desktop:

mobo - GA-Z97X-UD7 TH

CPU - I7- 4790K 4.0G S1150

Video - EVGA GeForce GT 740 Superclocked 1085MHZ

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I thought that maybe I could just swap out the video card for a suitable mojave-compatible ATI one.

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Is this worth doing or should I upgrade the mofo/cpu/ram as well? If so, what video card might work well for this set up? I use it for audio production (no gaming).