This mostly depends on when the drive was released and what memory was being used from which manufacturer, but currently the fastest USB 2.0 flash drives on the market are able to reach read and write speeds of up to 34 and 28 Megabytes per second respectively. Typically the manufacturer-listed flash drive speeds only apply to transfers of large contiguous files, whereas smaller files less than 1MB in size can dramatically slow down transfer rates due to the overhead for each file.