Heavy usage in peaks

Unfortunately, however I setup this plugin using recommended settings, I get occasional website crashes, and 1-2 minutes outages, and after that, website is back and everything is smooth. Using a single sidebar widget, on a 2gig 2cpu VPS. I can’t really figure what or why, but it happens randomly, even when I don’t have any widget on the website, plugin is just turned on. It seems it is ripping database apart with requests.