Ok so I have this SD card of 8Gb and I was wondering if it actually is faster than a 4Gb USB 2.0 HDD which spins at 4200rpm. I know both solutions are not very good but I use them for keeping things like MacOS X recovery and Windows Bootcamp tools and such, things that I don't regularly use. The thing is, I was wondering which of the two is faster and most reliable. Of course compared to each other (because this is what I got).