I’ve seen initial reports that at least on Steam Deck it’s far less impactful than any other recording solution available so far (decky recorder/obs/whatever). Like you though I’m interested to see a detailed look at how it does on a standard Windows gaming PC though, where you’ve already got well established low impact solutions like Shadowplay or Relive.
The machine I have running mint is a fifteen year old Core 2 Duo T6600 laptop. Works great!