Go into your Device Manager (you didn`t say which OS).
Under USB you should have something like Enhanced Host controller.
That is USB2.
If you haven`t got it, your on USB1.
Normally if you only have USB1, and you plug a USB2 capable
device in, you will be told `this device could perform faster`.
HTH.
Thanks HCH & Pen just checked where you said and 'enhanced' is there. It is
only 18 months old and I would of assumed it to be USB2 but you never know.