PC Build upgrade advice.

This is my current set up: https://i.imgur.com/vhvXvfH.jpg

The upgrade budget is roughly $500. What would you suggest? I'm thinking mainly getting a newer MOBO to get faster ram like 3200 or 3400 DDR4. What processors perform well with skyrim? I'll probably stick with my 970.

I use as much 4k textures as I can find.

Thanks!