I start playing this game with a Phenom x4 945 and Radeon 7850
This game is single thread intensive so phenom which isn't any good at single threading, you can image how low the fps is by mid and late game.
When playing with such low fps and staggering fps by mid and late game, you tend to focus your playstyle on rushes. Of course, you also end up being poorly knowledgeable of mid and late game units, the build orders and the timing but is just the matter of time you learn those.
I then changed to Ryzen 5 2600x. The FPS skyrocketed and my elo start climbing.
I then got a GTX 1070. Not significant difference, other than the fancy graphics more stable fps.
So a good single thread CPU make hell lot of difference in this game.
Does having better cpu improve elo?That depends how bad your current cpu is. If you are lagging by mid game, yes, it definitely will improve your elo.
If you however only start to lag by late game, the amount of elo improve I would say is insignificant.