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The Serial ATA drive and interface are faster than USB 2.0, so the USB 2.0 drive and interface are the "bottleneck". It may be that the source disk is newer and can push data faster than the destination disk can write it.Įxample: Backing up the data contained on a Serial ATA 6.0 drive to an external drive equipped with a USB 2.0 interface. the interface over which the data is moving.The computer will move data during a given transfer as quickly as it can, taking into account the abilities of all the devices involved in the transfer: Advertised transfer rates are based on the fastest speed at which the drive can send data back and forth across the cable (or bus) from the drive buffer.ĭata transfer will go as fast as the slowest device or busĪs technology progresses and newer, faster interfaces are developed, a user can have a collection of devices of varying interfaces, whose top speeds can vary widely. This table shows how much maximum total bandwidth is available per bus for each technology. Please note carefully not only the numbers, but also the units of measurement. Please see the below table to compare the maximum performance of each interface.
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