There are still a number of reasons why Avast might be slowing down your device. In most cases, Avast isn’t the one to blame for your performance drops. We’ll explore how to fix Avast antivirus slowing down your computer on Windows 10. If you want to enjoy the full protection of Avast, but don’t want to risk performance drops, this guide is for you. Does Avast antivirus slow down your computer? It’s possible, especially on lower-end devices.