Is there a way to reduce the lag between psychically moving the mouse until it moves on the screen?
I'm using Manjaro KDE Edition (17.1.10).
IN KDE you should be able to adjust the various speed settings pertaining to the mouse. I found this tutorial titled: how to configure mouse speed and acceleration in kde (k desktop env) which demonstrates in the GUI how one would adjust these mouse settings.
If you'd like additional insights into how to tweak/tune the mouse take a look at this U&L Q&A titled: How can I set mouse sensitivity, not just mouse acceleration?.
From the first tutorial that I linked to:
In KDE, you can find the mouse configuration in System Settings. Open System Settings and then navigate to Hardware Section, and then Input Devices. Select Mouse on the left hand side menu. Now click on the Advanced tab on the right hand side panel.