One of my computers has been extremely slow. After some investigations I found the culprit lied on the security software.
It was so slow as though the security software is checking every program execution and every network connection. So I just disabled it and the machine ran like a breeze.
I know I am supposed to get my computer protected, but what is the point if the protection will significantly cripple performance?
This bears analogy to how some nations (including two of the biggest and most important ones) trade off their liberty and security.
“They who would give up essential liberty, to purchase a little temporary safety, deserve neither liberty nor safety.” – Benjamin Franklin
PS
I installed another security software a while later. It seems to work fine so far, but I would not hesitate to uninstall if it cripples performance.