As noted in another thread, the log spam is expected. I turned it off as explained here:
http://www.antoniocortes.com/stop-di...s-in-yosemite/
Also I updated to driver version 2.3.
Nothing has changed for me
I am still experiencing the mouse lag on the external screen
The mouse lags, doesn't move as smooth as on the laptop screen and what's worse: it moves unpredictably. When I move my cursor somewhere on the external monitor, I often have to move it back, because it didn't land where expected