Hi @rasa, thanks for your query. Whilst our latest model of consumer eye tracker, the 4C will work with no issue on most USB2 (&3) ports, this is not the same situation for the EyeX.
Only USB 3.0 ports provides sufficient power and signal bandwidth for the Tobii EyeX Controller. Due to the required amount of bandwidth and power, the Tobii EyeX is not downwards compatible to e.g. USB 2.0. This means that if your USB 3.0 controller is not USB 3.0 certified, you might run into problems such as your computer not detecting the eye tracker or being able to use the eye tracking features.
Please let us know if we can provide any further information.