I have a Intel core i5 processor with USB 2.0. I wanted to upgrade it to USB 3.0. When I asked someone told me that i'll have to change my motherboard also. So I wanted to know that can I change it without changing the motherboard.
And plug in USB 3.0 capable devices into that add-on card to utilize the faster transfer speeds.
^ Yep that is the best way to do it without changing the motherboard. I have one running on my intel rig since it did not come with USB3 and it does work great. It just need a PCI-E single lane but will work in any from one to 16 what ever you have open.