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While copying a lot of files to an external hard drive using Firewire I notice that the copy speed is a lot slower than the Firewire data transfer rate. The supposed transfer rate for Firewire 400 is about 400 Mbps which is 50 megabytes per second. According to the program I have copying the files (Multicommander) the actual data transfer rate is 4 megabytes per second, more than 10x slower. What is the reason for this? (OS is Windows XP)
The magnitude of the speed failure is greater than can be accounted for by explanations like it takes longer to copy multiple files.
Tyler Durden
Posted 2015-12-26T19:15:38.990
Reputation: 4 710
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Possible duplicate of Why does certain files and collection of files take so long to copy?
– DavidPostill – 2015-12-26T19:20:50.2031your external hard drive might not support the speed, and anyway the spec is theoretical limit, you only get anywhere near when you copy a real large file. For real world copying, each file is rather small, and the overhead of starting a new file is dragging it down considerable. – Aganju – 2015-12-26T21:53:13.027
The magnitude of the speed failure is greater than can be accounted for by explanations like it takes longer to copy multiple files... on the contrary, it exactly explains the reason, especially if you have a very fragmented disk. Check out the answer @DavidPostill linked to, it explains why (i.e. disk I/O is expensive and 'transfer rate' is an up-to-limit, not a always-at-limit). – txtechhelp – 2015-12-27T11:33:56.173