I have searched long and hard and have found no way to independently adjust the tracking speed of the mouse cursor on a Mac. I'm running 10.11.6 El Capitan on my 2013 15" Retina MacBook Pro.
For whatever reason my mouse moves WAY faster horizontally than vertically. I have without success tried both USB Overdrive as well as Steermouse to see if they have any options that would let me adjust this. I've searched for ways to adjust this via the terminal.
At first I thought it was a Logitech mouse issue. I have been using a Razer Orochi mouse with the Razer Synapse software installed it's been working great. I wanted to try out a Logitech M705, and started noticing this issue. I tried installing the Logitech Control Center to see if that would help. No luck. Then I tried an Apple Magic Mouse, and noticed the vertical tracking speed is faster vertically than it is horizontally. Very odd.