LZO

configname: CONFIG_INITRAMFS_COMPRESSION_LZO

Built-in initramfs compression mode
└─>LZO
In linux kernel since version 2.6.33 (release Date: 2010-02-24)  
It's compression ratio is the second poorest amongst the choices. The
kernel size is about 10% bigger than gzip. Despite that, it's
decompression speed is the second fastest and it's compression speed
is quite fast too.

If you choose this, keep in mind that you may need to install the lzop
tool to be able to compress the initram.

depends
CONFIG_RD_LZO