Help me

I am currently having worse performance than i probably should, i have a good graphics card but i don't know what is "blocking" it's performance. I plan to upgrade everything sooner or later but i am taking it peice by peice. This is my current buildGraphics: AMD Radeon r9 390Motherboard: Prime a320 m-kProcesor: AMD athlon x4 950Ram : 8gb 2400I plan to upgrade ram, procesor and motherboard, I just want to know what should i upgrade first. Or any info on this would help a lot. Thanks