Did you know that there are two basic kinds of USB 2.0 drives? I didn’t. But, now thanks to Robert L. Scheier’s article, Not all USB drives are created equal, I now know that are significant differences between drives. And, in particular those differences matter a lot to live USB capable Linux distributions like Fedora 9.

The differences, in short, is differences in the memory type and their I/O controllers. The results are anything but trivial. One type of USB drive will run two to three times faster than their slower brothers and, potentially, last 10 times longer.

As Scheier explains, “The single biggest factor in USB drive performance is whether it contains one of two types of memory: SLC (single-level cell) or MLC (multilevel cell). SLC stores one bit in each memory cell, and MLC stores two bits in each cell.” The more expensive SLC memory runs twice as fast as MLC, “with maximum read speeds of about 14MB/sec. and write speeds of about 10- to 12MB/sec.” It also lasts much longer.

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