I has some personal interest in compression. Recently, I found this new compression tool: ZStd. It compresses much faster than gzip with better compression ratio.
For a not so scientific benchmark ^_^, to compress linux-4.4.34.tar (648867840 bytes) kernel, time reports the following:
time zstd linux-4.4.34.tar real 0m5.157s user 0m4.116s sys 0m0.534s time gzip -k linux-4.4.34.tar real 0m21.255s user 0m20.891s sys 0m0.175s time xz -k linux-4.4.34.tar real 4m21.785s user 4m21.430s sys 0m0.265s 648867840 linux-4.4.34.tar 132581836 linux-4.4.34.tar.zst (20.43%) 5.157s 137210920 linux-4.4.34.tar.gz (21.15%) 21.255s 90543184 linux-4.4.34.tar.xz (13.95%) 4m21.785s
It took zstd much less time to compress with slightly better compression than gzip. For a better benchmark, please refer to the zstd's home page.
There is a SlackBuilds package maintain by me for Slackware also.