March 22, 2011
-- There are probably some people out there that are not quite sure what the difference is between SATA external hard drives and USB external hard drives. The differences aren't extreme, but just knowing the difference between the two can help you make a choice.
First off, it's important to know that both SATA, which stands for Serial Advanced Technology Attachment, and USB, which stands for Universal Serial Bus, are both interfaces for external hard drives. Meaning they are both just a way to connect your external hard drive to your computer, although USB interfaces are also used for keyboards, mice, printers, etc. So in that sense they are the exact same thing. Where the difference comes is in performance and compatibility.
When comparing the two top versions of each interface, SATA revision 3 and USB 3.0, the SATA performs better. The raw bandwidth for SATA is 6,000 Mbit/s, whereas with USB it's 4,800 Mbit/s. The transfer speed for the SATA is 750 Mbyte/s, and the transfer speed for USB is 400 Mbyte/s. Now these may look like huge differences but we're talking about minimal noticeable difference in real world performance. Unless you're transferring GBs worth of data, the difference is minimal. And even when you're transferring GBs worth of data, you may only be looking at a difference of seconds.
One big advantage USB has over SATA is that SATA doesn't supply power to external devices. Meaning that you'd need a power adapter for your external hard drive if you were using an SATA interface. With USB, the power comes from the computer you're plugged into, so you don't need any external power devices. This is a huge advantage USB has over SATA, and it's a major reason why USB is becoming more popular. USB interfaces seem to not only be a great choice for external hard drives because of this power issue, but it makes it a great interface for other things as well. I have a MIDI keyboard that has a USB interface and it's really nice not having to have a power adapter to plug in as well. I just plug it into the computer and it's ready to go. It makes for great convenience.
So while SATA has a very slight real world performance over USB, it's not big enough to overcome some of the drawbacks. It's no wonder USB interfaces are becoming the more popular choice, it's simply a matter of convenience. And convenience is one of the most marketable benefits to products these days. Check out http://www.usb-external-hard-drives.com/whats-the-big-dea...
for more info on USB external hard drives.