We all know Morrowind is CPU bound, and no rig will handle it when you start really expanding distant land. Saw article how memory speed matters with current games like Witcher 3 and Fallout 4, quite a lot. So I changed from DDR3 1333 to DDR3 2133 and FPS went up almost 20% depending situation.

2560x1440 MGE EX 0.10.0 all shaders, 2xAA, 17 cells distant land, Morrowind Rebirth (which expands Balmora), and looking down whole Balmora FPS went from 17 to 20.

I also upgraded from HD7950 to GTX1070 and FPS went up in the same situation from 20 to 22 or about 10%.

So if you already have the best CPU, it might be good to upgrade RAM also as it is rather cheap nowadays.