This will vary quite a bit depending on what settings you have enabled. I can say that the primary MDE process sensendr.exe can hover at arounds 10-20% CPU if you have network discovery enabled, significantly less if you disable it. That's the process that does all the network inspection, so it will add some extra CPU regardless. In total around 100 MB of RAM, not too bad. But other's observations will vary if they have more functions enabled.