The

main effect of this is allowing the computer to cache the OS Kernel to memory, making the OS more responsive. The setting is dynamic and if more than 4 MB is needed from the disk cache for some reason, the space will be released to it. By default, 8MB is earmarked for this purpose. This tweak usually makes the OS more responsive. It is a dynamic setting, and the kernel will give up any space deemed necessary for another application (at a performance hit when such changes are needed).