No I'm not a gamer, which is why I asked and that was mainly to see if there was a specific problem that you have.
Life is about decisions/compromise and you have already made some by purchasing high end expensive video card and processor for your gaming entertainment, but what if you can't play the game because of infection. There has to be a compromise between performance and protection, the people you are playing against aren't the problem, but port probing by bots and then attack on your system. Any malware that does happen to get on your system is going to be using up valuable system resources too.
avast is designed to be a resident scanner and you can't easily shut that down (all services, etc.) as you would effectively need to reboot it to get it started again. Have you tried a right click on the avast 'a' icon and select 'Stop On-Access Protection,' this stops the scanning but the services are still up, but allows you to click the same option start on-access protection.