Monday, March 05, 2012

The Best Free Compression / ZIP program: a comparison

The Best Free Compression / ZIP program: a comparison:

The best free compression program illustrationA Zip/compression program is an essential fixture on any computer. There are so many excellent free compression apps that I am always astounded when someone asks me if there is a good ‘Winzip’ alternative out there. But the real question is: which is the BEST free compression/archiving program available. We set out to test what we thought to be the best free compression programs in a head-to-head QUANTITATIVE comparison, where we collected actual compression and extraction data on different system. We also took other, qualitative aspects into consideration, such as the features, the appeal of the interface, etc. What we’ve found: three programs are in a league of their own; HaoZip, 7Zip, and PeaZip. Our preference for these is in that order, respectively.

Table of contents:

  1. The list of programs that were selected

  2. The verdict: giving an opinion upfront

  3. Assumptions and Priorities: why we made the decisions we did, and what we cared about most.

  4. Context and variables: more complicated than we thought.

  5. System Specs: the environments we used to test

  6. The tests: extraction and compression

    1. Compression ZIP: Best overall compression performance for ZIP format

    2. Extraction time: multi part UnRAR

    3. High compression ratio performance (7Z format)

  7. Feature Comparison

  8. Formats Supported

  9. The Raw Data

  10. Credits

1. The list of programs that were selected.

We tested the following versionsof there programs on 32bit and 64 bit environments.

WinRAR7-ZipHaozipPeazipIZArc ArcthemallTUGZipIceowsHamster
v4.01 (not free)v9.20v2.4.7228v4.1v4.16v4.6.1v3.5v4.20bv2.0.0.16

Note that WinRAR is NOT FREE; however we included it in our tests for benchmarking purposes, since it is considered by many to be the archiving program of choice. Why did we choose these and not others? See assumptions and priorities below.

Download links: click on the links below for the program home pages.


2. The verdict: giving an opinion upfront

The answer to the question “which compression program is best” depends on what you care about (see the section below)”. However, if I must give a recommendation I will say that my personal choice would be HaoZip, 7Zip, (tied for first place), and then Peazip. Here’s a comparison table for the three: note that the rating scale differs per each item based on how much weight I think it should have.

Overall performance for ZIP (savings ratio + processing time)9/1010/108/10
Extraction time multi part RAR10/1010/107/10
High compression ratio performance (7Z format)5/55/54/5
Offers all features you would expect in a modern archiver (multi part archive creation, self extracting archive, etc.)YESYESYES
a good looking interface,YESYESYES
Offers a dedicated 64 bit versionYES (in a single download)YESYES
Excellent performance on both 32 bit and 64 bit, both low spec and high spec systems (something not to be taken for granted, btw)YESYESYES
Context menu support for both 32 bit and 64 bit.YESYESYES
Support for a wide range of COMPRESSION formats2/3 ZIP, 7Z, TAR2/3 ZIP, 7Z, TAR, WIM3/3 ZIP, 7Z, ARC, BZ2, GZ, PAQ, PEA, QUAD/BALZ, TAR, UPX, WIM, XZ
Support for a wide range of Extraction formatsYESYESYES
In-development and frequently updatedYESYESYES

3. Assumptions and Priorities: why we made the decisions we did, and what we cared about most.

Assumptions: Here’s an overview of some of the decisions we made in our test and evaluation.

  • Why we chose the programs we did: we wanted to include all ‘serious’ archivers that were 100% free. We preferred programs that had had recent releases and/or were still in development, but anyway ended up including programs that were not updated in a long time. We excluded Jzip, a program that we liked when it first came out, because it sneakily installed toolbars and crapware by default and buried the option not to do so in the ‘custom’ install option.

  • Why we looked at the formats we did: we looked at ZIP, 7Z, and RAR for WinRAR only. This is because ALL programs (save WinRAR) supported these two formats, so we could compare them. We included RAR for WinRAR in the tests for benchmarking purposes. We are aware that the selection of ZIP and 7Z may have played a role in determining the eventual ‘winners’ (esp. 7-Zip), but we estimate that these two formats (and RAR) are the most popular on the internet anyway.

  • Why we chose a multi part RAR for the extraction test: we extracted an extremely large multi part RAR archive. Why RAR? because extremely large multi-part RAR archives are the most prevalent type of archive, found all over the internet, and we wanted to know what programs were best at handling these.

  • What is meant by “overall performance”: this is a concept that is meant to gauge the most efficient trade-off between savings ratio on the one hand and time to process on the other. For example, I would consider a 14.7% savings ratio which takes 300 seconds to finish to be a better result that a 15.03% savings ratio at 700 seconds (the difference for the 1.32 gig basket of files is a couple of megs extra savings). I understand that this is a CHOICE, to say the former is better than the latter; others might have different prerogatives, and may evaluate the data differently.

Priorities: here’s what we cared about most These are the priorities we considered that this analysis will prejudiced by. Those who have different priorities can nonetheless read this article according to their different point of view; I hope that all the data and analysis are clear and easy to work with.

  1. Compression ZIP: Best overall compression performance for ZIP format. I.e. delivers the most efficient trade-off between compression ratio and time taken for ZIP output format, as explained above

  2. Extraction: best extraction time of large multi part RAR archive. I.e. performs best on extracting large multi-part RAR archives

  3. Features and interface… has the features you would expect in an archive program, a nice, user-friendly interface, set and good context menu integration in Windows Explorer.

  4. Compression 7Zip: Best overall compression performance: delivers the most efficient trade-off in creating a high-savings ratio 7Zip archive, and time taken to do so.

  5. Supported formats: this we cared about LEAST. The reason: all of them extract a huge range of formats; however, if you want to COMPRESS using a specific format that is not ZIP or 7Z, then you will have to shop carefully to find an archive program that delivers what you want.

  6. Whether it’s still in development: and whether there is a dedicated 64 bit version.

4. Context and variables: more complicated than we thought.

At first we wanted to test each software’s speed of compression, speed of extraction, and variations in size savings. However, we soon discovered that matters were much more complicated: each program had several compression ‘profiles’, and different compression formats. Moreover there were large differences in performance between 64 bit and 32 bit environments, and between more powerful and less powerful machines (particularly in 32 bit). Below is the list or relevant variables.

  • 32 bit or 64 bit

  • Extraction vs. Compression

  • Format used: we only looked at ZIP, 7z, and RAR for WinRAR

  • Profile used (typically called ‘max’, ‘fast’, etc). Refers to how much ‘work’ the program will put into the compression process. See “what the bleep is a profile” below.

  • Whether the PC was powerful or not (specifically, how many CPU cores were at play). Some programs performed admirably in a high specs configuration but miserably in less powerful machines.

The sizes and compression times were all over the map for different profiles and compression formats. Coming up with an answer to the question ‘what is the best freeware compression program’ was not going to be easy, and would largely depend on the user’s priorities. But I do have an answer to the question, albeit with caveats.

What the *bleep* is a profile? Every program has multiple compression profiles depending on the compression level and format. The essential tradeoff here is time: you determine just how much the program should try to compress, and it will implicitly take longer in processing. Typically, each program will offer 3 to 6 ‘profiles’ per each format. The screenshots below illustrate two examples of what we mean by profiles (for HaoZip, Hamster).

HaoZip ProfilesHamster Profiles

5. System Specs: the environments we used to test

We tested on 3 configurations. For 32 bit we ran virtual instances of Win 7 32 bit on VMware, since we did not have access to a physical machine running Win 7 32bit. All ran on the same (7200 rpm) hard drive, which is where all testing operations took place.

64 bit32 bit-1 Low spec32 bit-2 High sepc
OSWin 7Win 7 running virtually on VMWareWin 7 running virtually on VMWare
CPUIntel core i7 q740 @1.73ghz (8 processors)Intel core i7 q740 @1.73ghz (1 processors)Intel core i7 q740 @1.73ghz (4 processors)
RAM5GB2256 Megs2125 Megs

The difference between 32 bit-1 and 32 bit-2 is that the latter had more resources / CPU cores available to it. We found that for some of the programs we were testing, this made a huge difference.

Click here to go to page 2 of this article (for test results, feature comparison, etc)

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