Personally, for my standalone core, I've always just used whatever motherboard/graphics I have laying around, regardless of brand/performance. Or buy a mobo that ticks all the boxes, without caring about graphics. Even if the screen does appear the size of a matchbox, why do you care. But this is just my experience. You could always stick an older nVidia graphics card in if you had serious problems.
Don't piddle about buying old kit to match your old CPU, just cough up and replace it all, doesn't need to be particularly powerful.