Why is cp command 4 times slower than copying in Finder in OS X 10.6?

I accidentally stumbled upon this issue:

Copying a 119 MB zip file took 4 times longer in Terminal (cp) than in Finder!

I copied a file of 119 MB size in Terminal with time cp file.zip file2.zip and it took about 20 seconds.

As this seemed quite slow to me, I went to the Finder, selected the same file and hit Cmd-D (duplicate) and it took less than 5 seconds to create the copy, that is only 25% of the time it took with cp!

Is there an explanation for it - might this be systematic?

Used Hard-/Software

• MacBook 13" white (2007)


• OS X 10.6.8


• Internal hard disk WDC WD10JPVT-00A1YT0

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it really seems to be a cache issue: I tried the opposite order with another file and copied it first in Finder and then in Terminal, and in this case also the second copying was much faster.