Coming from Intel, I'm curious on which would be normal idle/stress temps for the Ryzen 5 3600 that I'm running with the Corsair H55 water cooler. It idles at 58/60 and is reaching 90, 95 degrees under load and, eventually, turns off completely.
thank in advance for any advice
Way too high, either your installation method was faulty, or the cooler is faulty. The R5 3600 is an 80w processor at most, which is well within the H55's ability to keep below 90*C.
Something to remember too is that closed loop liquid coolers are only good for around 7 years or so. Even though they are sealed they do lose a -tiny- bit of coolant over time, which eventually will manifest as an air bubble large enough to hinder performance, or even lock it up.