I don't run any overclocks, so I find that CPU & GPU temps are just fine with coolant as hot as 50C. To me, "just fine" means there is no thermal throttling and temps are at or below what they were using the stock air cooler and fan curve (where applicable).
I currently have my target coolant temp at 38C and was just thinking that the loop fans could run slower and the room air conditioner could run less if the coolant could be 45C instead. But I also don't want to put the loop in danger by running it too hot for months at a time.
When I see coolant temps that people post on various forums and subreddits, I'm always left thinking the person is either a liar or an idiot
I see claims of 25C being normal from people who are clearly lying and claims of 60C being just fine from people who have hacked together loops that make my face twitch when I look at them. So, I've never really known what temp to be shooting for.
I'm kind of hoping that someone from Aquacomputer will see this and share a number. Literally everything in my loop is from them except for the rads (they don't have a size compatible with this case, so I'm using Alphacool) and barbs (which they don't make, so I used Alphacool). If there is anyone on this planet who knows the highest safe temperature for continuous use, it is someone who works there.