That is indeed true for very low levels, however, as the instrument is set to source voltage and measure current, I would expect noise to predominantly affect the y-axis (current) of the plot, as the voltage to sweep continuously as defined by the sweep generation TriggerFlow script. Instead, we see some bouncing back and forth on the x-axis (voltage) which is not expected and could be related to other issues experienced with this particular SMU unit which likely has a hardware defect. Please see the full in-depth blog posting for further details.