How to disable Avast completely?

I was wondering if there was a way to kill off Avast’s task until I opened Avast again, just for when I play some games, because it takes up around 4% of CPU and almost 160MB of RAM and that affects the game’s performance.

I’m afraid to ask, what kind of computer you have that 4% CPU would affect your game’s performance in any noticeable by human way…

As for 160 MB of RAM… Unless you have less than 1024 MB of RAM, it wouldn’t affect anything at all for you (besides, I suspect you have at least 8 GB of RAM, considering you imply to play games with very high system requirements). It just wouldn’t be noticeable at all and wouldn’t make any difference.

If you wish to stop something (short of uninstalling Avast completely), there are only shields.
It’s enough to just stop all its active shields (don’t forget to enable them back), which can be done through its icon in your taskbar’s tray area.
And it shouldn’t affect anything at all after that.

Most likely, your issues with games are because of your graphics drivers.

Also, by my experience (and by what gamers often say on various forums on the internet),
the most recent drivers aren’t always the best case.

Sometimes people have stable drivers for their graphics card, and then try to update, and no new drivers ever work as well, and they begin to experience issues and have to roll back.

If you have old drivers, you can try most recent though, if you do have most recent, search for people’s possible performance issues with your current graphics drivers, and most likely you will find them recommending to switch to specific older drivers.