Although I'm using Windows 10, I can report that I have experienced general performance degradation with EIS while performing I/O intensive tasks, like large copies over lan, large copies from one disk to another, or large game installations from GOG installers (these are very disk intensive). Whenever doing any of these activities, desktop responsiveness degrades, and interacting with any software becomes laggy, mouse clicks sometimes won't register or have some delay, Firefox/Brave becomes slow to display pages, scroll up and down, click on page elements. And this is on a beefy system with multiple SSDs.
I have noticed similar behavior, albeit less severe, when EIS performs full system scans, or when opening a lot of web pages simultaneously, where network performance often degrades as if EIS is unable to handle several network requests in parallel. I'm not certain on how Eset handles I/O operations, but the symptoms are as if EIS is getting saturated, consequently bottlenecking my I/O performance.
None of these problems occur after removing EIS and using either Microsoft Defender or Kaspersky.