A lot of the time people on here say, "update your graphic card drivers" and 9 times out of 10 that is a ridiculous suggestion because it has nothing to do with the things most apps need to do, especially not audio apps.
This, however, looks like the 10th time out of 10. If you do not have the proper graphics drivers, the OS may have to perform a slower operation each time you move the mouse cursor to be able to redraw the area that was under the mouse and draw the mouse in a different position.
A similar story applies to the drivers for the mouse itself - most mice should work perfectly as generic USB devices but there is a chance that your mouse is somehow strange and it is requiring more CPU usage than usual to track the movement. This is sometimes the case if you have gaming mice that poll at 1000Hz or whatever - they basically have to tell your OS "hey, I've moved! Make a note of my new position" far more often than a normal cheap mouse, which takes time and interrupts other processes.
Finally, try changing USB ports for the mouse and the Octacapture - perhaps they are both on the same USB hub (which might be internal) and are competing for notification bandwidth.