The slowdown from using ANY antivirus program occurs in 2 different ways.
obviously when a full scan is running the system is slowed down, this is resolved by scheduling the scan to occur at an "off" time.
second, when accessing files or running executable files the antivirus is running, this is happening in real time as you are working. when you open the task manager your av program may not be using many resources, but if your browsing, opening/closing files, etc... the av software will use more. turning this part of the av software off means you would only know about a virus on your weekly scan, not live.
i do not allow my antivirus to do realtime scanning, only the weekly scans. in theory this puts me at a greater risk but allows for better performance. I mitigate the risk by using a program called sandboxie.
sandboxie creates a small area of space on your harddrive called a sandbox. when you open firefox,outlook,etc... from within sandboxie anything that you download is held in the sandbox. when you empty the sandbox its gone.
antivirus software only works on a known virus. the only way they can be known is that a certain % of the population has become infected thus allowing the av software writers to study the virus and recognize it in the future.
Market Data 
Markets 
AI
