If your voltage stages are unstable (ie: power stays on, but the actual voltage amount varies a good deal with the 220V standard), then I think that's the sort of scenario in which an AVR is helpful. I have just purchased a brand new Laptop with the Intel core i7-920 https://alexisnoonl.idblogmaker.com/32987648/not-known-details-about-uninterruptible-power-supply-definition