Hello,
They should work, presuming they are backward compatible. If they are dedicated 3.0 then no they won't work.
Go to Control Panel, Device Manager, click on USB devices. Find your two 3.0 USB ports, do they have just the 3.0 driver listed or the 2.0 and 1.1 drivers as well? That's how you can tell if they're backward compatible.
Let me know if this helps you out.
Regards,
BearPup