Using both SS & VS should have little or no impact on a contemporary computer. I use both, at times, on my aging laptop (vintage 2012) with no perceptive slow-down or conflicts. VS & SS offer very different types of security protection. Running them both constitutes *layered security*.
For any given attack, VS & SS might both catch it, or VS might catch it & not SS, or SS might catch it & not VS. THAT is exactly why someone might choose to use *layered security*.
IMO, only a higher-risk user would need to layer VS & SS. Most users will be just fine with nothing more than frequent imaging and a top-tier AV.
