Quote Originally Posted by chithanh View Post
xz (lzma) is an ok choice, but it is by far not the best compressor. The only advantage is that it is already installed by default almost everywhere. If decompression speed is important, then e.g. lzham would be more suitable.

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Decompression speed is indeed important, but so is compression ratio. So any choice in this matter will likely weigh in all factors and I guess that for package distribution, compression speed is the least important factor as it is not something which affects end users. Compression on the other hand affects the time it takes to recieve the packages and decompression speed affects the time it takes to install them once they are downloaded.

So a solution which provides great compression and great decompression speed is likely a prime candidate. On my machines the packages I get from the Arch repos (xz compressed) unpack and install very quickly but then again I have a core i5 and a core i7 so it's hard for me to judge how effective it is overall.

Still, lzma should have proved itself as striking a good balance between compression/decompression speed and compression ratio given that it is used in so many compression tools.