IDG Answers is a community of experts who are passionate about technology. Ask a question or answer one below.
I found this really interesting site called Diffen that allows you to compare two things. And not just technological things (though I'll get to that): The top 5 listed on the site include "Democrat vs. Republican" and "Empathy vs. Sympathy."
This is Diffen's answer for USB 2.0 vs. USB 3.0. You can click on the link to compare specs, but here's the answer to your second question:
"USB 3.0, the latest version of USB (Universal Serial Bus), provides better speed and more efficient power management than USB 2.0. USB 3.0 is backward compatible with USB 2.0 devices; however, data transfer speeds are limited to USB 2.0 levels when these devices inter-operate."
Thanks for the answer. I'm not sure whether I should be happy or not that you turned me on to Diffen, though. I checked it out and next thing I know I had spent almost an hour comparing random things. It would be very easy to go down the rabbit hole on that site! Buzzfeed, Redit, and Diffen could pretty much kill a day if I'm not careful!