ISO 3166-2 geocode for Argentina. This is used as an international standard for shipping to Argentina. Each Argentinian province has its own code with the prefix AR.. For example, the code for the Province of Buenos Aires is ISO 3166-2:AR-B.
The USB 2.0 interface can be a limit due to signalling and command overhead as well as spacing between packets. I have a fast SSD connected by USB 2.0. The drive is much faster than the interface (by more a factor of 10). Read Speed maxes out around 33 MB/s and Write Speed at 17.5 MB/s. Write Speeds are almost 50% slower due to a verify-read after the write and the fact that the USB signal is half-duplex as another answer mentions.
USB 3.0 - Breaking the Length Barrier. The new USB 3.0 standard has dramatically improved the connection between hosts and peripherals across the world. With its SuperSpeed data transfer rate of 5 Gbit/s and current delivery rates at 900 mA, USB 3.0 has improved upon and supplanted USB 2.0 in numerous applications. Despite these improvements in electrical performance, USB 3.0 is significantly limited by its shorter cable length requirement. In April 2013, an update to the USB-IF compliance for USB 3.0 standards restricted A male to B male cable lengths to three meters maximum.