If you're planning to upgrade to the upcoming Ubuntu 18.04 LTS (Bionic Beaver) operating system this spring, then your computer will boot a little faster thanks to the implementation of a stronger compression algorithm for the initial ramdisk.
Canonical's Balint Reczey has proposed implementing LZ4 compression in Ubuntu's initramfs (initial ramdisk) instead of the older gzip compression used in previous versions of the operating system. LZ4 is a data compression algorithm that offers extremely fast compression and decompression speeds.
During some initial testing on an old laptop, the developer reports that initramfs extraction time was reduced from about 1.2 seconds to about 0.24 seconds. Creating initramfs also received a 2-3 second speed boost, down from about 24 seconds to about 21 seconds, despite the slightly larger initramfs files.
While Ubuntu 18.04 LTS (Bionic Beaver) will be the first to ship with the LZ4 compression option for initramfs, it won't be enabled by default. So you'll have to enable it manually if you want your Ubuntu computer to boot a little faster than usual. Canonical plans to enable it by default in Ubuntu 18.10, which is due for release in October 2018.
On the other hand, it appears that the LZ4 compression algorithm creates slightly larger initrd files, but the developer states that this will not affect future versions of Ubuntu due to the update manager's ability to remove old kernels to prevent the boot directory from overflowing with unwanted initramfs files and kernels.
