Here is the advantages to changing out to USB 3.0 it brings you into the next generation of computer speed. Transfer speeds are lighting fast. I use mine for backups. It is backwards compatible so no worries you can plug in a USB 2.0 device and be fine. Plus adding the card vs changing out the motherboard is not only cheaper but it wont force you into additional upgrades.

See if you changed out your motherboard to one that is 3.0 then you will be forced to upgrade everything basically. Here is an example of one (they all basically look the same specs wise) of a motherboard that supports USB 3.0 by Gigabyte. That motherboard will set you back around $350, however if you look at the memory (RAM) you are now going to have to upgrade to DDR3 and for the CPU to a i3 or above. In the end your looking at around $1400 (or more) and that doesn't include the hard drive(s).

By upgrading this way you are looking at only $100. for the card and the external case. Now what about the hard drive well if you don't have one they are not that badly priced. For a example here is a Western Digital 1TB 7200RMP
for under $100, so drop that into the case and your only out ~$200 for everything. Or if you want you can skip the whole external case and bare hard drive and having to install it and get one that is already a USB 3.0 like this one: CLICKY