What is the Best File Compression Format? – See Results!

Haven’t you ever wondered what the best file compression format is? Here at GeekyProjects we try to answer this question. We have performed a test of three popular compression formats; 7zip, Rar and Zipx. The test is not overly scientific or comprehensive, but it shows clear differences among these popular formats. Winrar and Winzip were used to compress the Rar and Zipx formats respectively, 7Zip was used to compress the 7zip format. The tests were done in a computer with a 2.53ghz core2duo processor and 4GB of memory. Before we start we must define what the term “Best” means in this article. “Best” simply means the format that compresses the most. In our opinion, the most important characteristic¬† a compression format should have is its ability to compress. Compression speed and resource consumption are also important, specially if you are compressing large files, however, differences in time, CPU and memory were not significant enough in our tests to be influence our results.


Big File Compression Test

This test was done combining a variety of file formats, including, documents, ISO images and pictures.  All compression formats were tested at their maximum compression level. Since we were compressing a large folder, we decided to also record the percent of CPU and memory used. As you can see the winner here, although not by much, was 7zip.

The original size of the folder we compressed was 1.61GB.


Cpu % Used Mem (4GB total) Time Compression%
7Zip 79% 1.05GB 12:59 min 9.4%
Zipx 87% 483MB 11:39 min 8.1%
Rar 95% 450MB 9 min 8.7%


Document Compression Test

For this test we collected a variety of text files and documents. We copied them all to a single folder which ended up being 41MB. In this test is where we were able to observe the real power of compression. Take a look at the results displayed in the table below. The poorest performer had a 64.6% compression ratio! Here, however, was where 7Zip really shined: It performed well above the rest, achieving an 83.6% compression ratio.

The original size of the folder we compressed was 41 MB.


Time Compression%
7zip 11 Sec 83.6%
Zipx 18 Sec 68.8%
Rar 13 Sec 64.6%


Image Compression Test

For this test we used jpeg files exclusively. Here’s where finally 7Zip lost its crown. Newer file compression formats are optimized to compress pictures and other already-compressed formats such as mp3 files. The winner here was ZipX , which was compressed using the popular Winzip. However, as you can see it took mote than twice the amount of time it took to compress other formats.

The original size of the folder we compressed was 50Mb


Time Compression%
7zip 41 sec 20%
Zipx 100 sec 24.2%
Rar 35 sec 18.6%


Final Thoughts

As you can see by the results, compression ratio by format depends on the type of file being compressed. For documents and any other uncompressed  files, 7Zip is the clear winner. For Pictures, go with ZipX. If some of you are wondering why the Zip format was excluded from this test, it is because, while it is the most compatible format, it is a very old format and and it does not even come close to challenge newer formats, like the ones tested.

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