What is Data Transfer Rate?

R. Kayne

A data transfer rate (DTR), is the speed at which data can be transmitted between devices. This is sometimes referred to as throughput. The transfer rate of a device is often expressed in kilobits or megabits per second, abbreviated as kbps and mbps respectively. It might also be expressed in kilobytes or megabytes, or KB/sec and MB/sec. Bits are abbreviated in lower case, while bytes use upper case.

The speed at which data can move from an external hard drive to a computer is the transfer rate.
The speed at which data can move from an external hard drive to a computer is the transfer rate.

1,024 bits = 1 kilobit (Kb)

A SATA cable, which is used to transfer data.
A SATA cable, which is used to transfer data.

8 kb = 1 kilobyte (KB)

128 KB = 1 megabit (Mb)

8 mb = 1 megabyte (MB)

1,024 KB = 1 megabyte (MB)

128 MB = 1 gigabit (Gb)

8 gb = 1 gigabyte (GB)

1,024 MB = 1 gigabyte (GB)

In a world where programs and files are becoming ever-larger, the highest data transfer rate is often the most desirable. However, as technology moves quickly to advance the speed of many components, consumers are often faced with systems that incorporate varying specifications.

For example, RAIDs (Redundant Array of Independent Disks) consist of multiple hard drives linked together to be pooled into one large storage system. The virtual drive that results can be several hundred gigabytes. When programs are initiated or files retrieved, the data transfer rate of each drive becomes important to reach across this vast storage pool. Drives are rated by how fast they can read and write data. An Ultra ATA drive is rated at 33.3 MB/sec, while a SATA 300 has a rate of 300 MB/sec. The RAID is forced to adopt the speed of the slowest drive so as not to lose data as it travels across that disk from faster drives. For this reason, it is best that all drives in the RAID are of the same model and manufacturer, so that they will support the same data transfer rate.

It is also important to consider data transfer rates when purchasing controllers. If buying a SATA controller, for example, be sure it supports the rate of the SATA drive(s) you plan to use. A SATA controller that supports the SATA 150 specification only will slow a SATA 300 drive down to half its designed speed. A controller that supports the newest version of SATA will be backward compatible to run slower SATA drives as well. For this reason, it is always best to buy components that support the fastest speeds possible.

Modems, cables, controllers, optical drives, printers, scanners and virtually all computerized components feature a data transfer rate. Taking this into consideration is one of the most valuable tools in choosing new components and upgrading old ones.

A gigabyte can hold the information equivalent of about 1,000 thick books.
A gigabyte can hold the information equivalent of about 1,000 thick books.

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Discussion Comments


Well, DTR is the amount of data to be transferred from one location (device) to another location (device). DTR varies from devices to devices and also if we are transferring serially or parallel.

For example, the DTR of an external hard drive using usb2 can be max up to 480Mbps comparatively to this - same hard drive with USB3 could transfer 10 times more data. DTR was initially measured in bps (bits per second) but now it reached in Gbps (gigabits per second).

i hope this will help. if you have any questions, please post here and i will try to answer. --Amber


Why does data transfer rate slow down from a moving vehicle when using a smart phone?


What is the highest DTR of a hard drive?


why do I have a DTR on Yahoo Mail as low as 35Kb and I can't do anything to improve it.


You didn't say what DTR you are measuring (between which devices), nor did you specify bits, bytes, etc.


My data transfer rate varies from 49 up to the high 300's. Why? I was told by a tech to do a full recovery of my system, which I did, but it's still variable. Is this normal?

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