Which of softwares is for managing cache
 

My computer suddenly get a terrible slow operaton.I think of some wrong with my computer's cache.Thanks.

You're not actually asking a question yet. Can you tell us what is slow - applications starting, system booting, network transfers? Do you get any error messages?

Thank you.Almost applications:starting Mozilla,switch to command line etc.It always get better when I restarting the computer.

Open up an xterm and run the top cmd; keep an eye on this while using the computer, it should point you in the right direction.

Open a terminal and use the top command to see if there's anything hogging the CPU or memory. Hopefully you can track down the issue. Linux caches aggressively (unless you tweak it) so it's probable that some program is eating up too many resources (or your hardware is insufficient for the apps you are running).