+ edit read_ahead_kb via "STweaks"-App

"Maximum number of kilobytes to read-ahead for filesystems on this block device. Maybe get better read-performance with higher value, but you will probably need to experiment and benchmark (e.g. with "SD Tools"-App) to find the best value for your sd-card / system and maybe you will have a higher overhead (less memory) with a higher value." - so we made it optional ...