I noticed Chrome OS is more efficient than Windows, so the same CPU in Windows will be about 3 times faster in Chrome OS, from some rudimentary measurements I made. So a later generation Celeron on ChromeOS is plenty fast, no need for i3 or i7. However i also noticed that 4gb ram is not enough. I bought the ASUS CHROMEBOX 3-N017U  with 4 gb ram and I added an additional 8 gb ram ( https://www.amazon.com/gp/product/B019FREJOQ/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 ) , and it is very fast, even with 40 tabs open. From my experience, Chrome OS has made Windows and MacOS almost obsolete, and only necessary for some specialized applications like Visual Studio or Photoshop. And even for those, its better to have a Windows desktop in a corner and access it remotely from ChromeOS using RDP.