What computer anti-virus software uses very little memory while maintaining maximum protection?

I recently installed Kaspersky Antivirus onto my computer after Webroot failed to pick up four nasty infections. Its not like I don't like Kaspersky, but it is absolutely destroying my computer. When I do a scan, my CPU Usage (according to Windows Task Manager) skyrockets from something like 12% to 90%. Also, when I try to watch videos and browse things on the web, my computer will have random glitches and freezes. Its almost unavoidable. I don't think its a virus because I scan my computer at least once per day. Also, I never visit malicious or known infectious sites. But, for some reason, my computer just doesn't work like it used to. I think its Kaspersky. I intend to purchase a new gaming computer soon, so I need to make the most out of my memory while maintaining maximum protection so my accounts and information don't get stolen. Does anyone have any recommendations? I have heard ESET Nod32 is good. However, I haven't done much research because my computer is rendered useless thanks to a problem I believe is caused by Kaspersky. Thank you in advance!