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Date:      Sat, 21 Mar 2009 01:53:16 +0200
From:      Ghirai <>
Subject:   speed in extracting rar files - unrar vs. 7z
Message-ID:  <>

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Does anyone know a faster way of extracting big rar files, or why is
it so slow?

I did a quick test with time (extracting the same ~800MiB file,
consisting of split archives):


real	4m29.637s
user	0m4.969s
sys	0m3.131s


real	3m50.020s
user	0m4.784s
sys	0m1.821s

While not a very good test, as i was having other apps idling around at
the time, i did notice that neither of them were fully utilizing the
CPU (Core2Duo E6550, clocked at 2.9GHz).
Usage was ~8% at most.

As you can see, 7z is marginally faster.

The shareware WinRAR on windows seems to be better implemented (?), as
it uses both cores to the fullest, and as such the time needed to
extract stuff is a lot shorter.

If this an implementation problem in unrar/7z, or is it the scheduler's
'fault' so to speak?
Or does it have something to do with disk IO? If so, how do i check,
and how can it be improved?
Looking at top again, while extracting, showed both apps' state to be
getblk most of the time, if it matters.

I'm running 7.1-RELEASE, i386, generic kernel.

Any ideas/thoughts?


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