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    Compression, Backup etc.

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    Almael
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    Compression, Backup etc.

    Post by Almael on 7/29/2014, 2:13 pm

    Since last year there's a new RAR5 compression protocol now with winrar 5.1 the bugs got resolved and it got more support. Naturally I was interested in testing it out.

    237 mixed binary & text files 41480928 B
    v393 8362037/8402887 B zip 20%
    v393 old 6938367/6958550 B rar 16% 4 MB dictionary
    v393 now 6960290/6980473 B rar 16% 4 MB dictionary
    v401 8439609/8480459 B zip 20%
    v401 7387731/7408146 B rar 17%
    v510 8338450/8387940 B zip 20%
    v510 6959289/6979472 B rar 16% 4 MB dictionary
    RAR5 7318509/7358513 B 17% (defaults to?) 4 MB dictionary
    conclusion:
    - difference between zip & rar as expected
    - new is better now, inconsistancy of v393 rar points to pure-old is better
    !possibly OS switched to new driver file as default after installation

    200 jpeg files only 75226758 B
    v393 74713237/74779485 B zip 99%
    v393 74824869/74859615 B rar 99% (defaults to?) 512 kB dictionary
    v510 74714803/74825167 B zip 99%
    v510 74819710/74854456 B rar 99% (defaults to?) 512 kB dictionary
    RAR5 74860968/74928922 B 99% (defaults to?) 512 kB dictionary
    conclusion:
    - difference between zip & rar as expected
    - old is better

    27 tiff files only 450623846 B
    v393 138831508/138833702 B rar 30% 4 MB dictionary
    v510 135840063/135842257 B rar 30% 4 MB dictionary
    RAR5 144910435/144915286 B 32% 128 MB dictionary
    7-zip v9.2 LZMA2 64 MB 273 word size
    149770373 B

    All in all it seems older versions are (a bit) better at compressing (zip/rar) despite using the same compression driver version. Since I installed winrar 5.1 my older version aren't clean anymore. Each time I start a new test it's bigger than the original packages done by the clean old version.

    RAR5 is meant for video files. Since it gives you 5-15% advantage I figured it would only give enough usable free space if at least 500 GB has been compressed. I don't see a reason to do this other than when making backups.

    If you add the recommended 5% recovery information, well, the savings would be gone. In general old rar format is useless regarding recovery. So I never used it. But rar5 finally (after 15 years) got a good recovery record technique. Heh.

      Current date/time is 9/24/2017, 3:15 pm