Safe temps for F4-3600C16Q-64GTZN?

[mta]

What are the safe temps when overclocking for long-term 24/7 usage? Right now I am at 3800Mhz CL16 trying to crank down the memory subtimings, but I am noticing that DIMM temps are starting to climb to mid-60C temps during memory stress tests like Karhu (takes about 6 hours to hit 6400% coverage). Is this safe?

I read everywhere that b-die starts to become unstable around 40 or 50C, but for me I'm already getting stock dimm temps of 40C, and even when the dimms get hot in the mid-60C range, so far they have remained stable with the right settings. I want to see what these sticks can do but I also don't want to damage something.

What's the max safe voltage for daily OC use? Right now I'm at 1.45v. Would even 1.5v 24/7 be safe? What about safe 24/7 temps? Would 65C under load be safe? 70C? 75C? I've seen a few posts mentioning that they hold up to 80C but I don't know if that's an absolute max before something breaks, or a safe long-term temp, etc.

[emissary42]

The stability threshold for B-Die varies from one kit to another and is also dependent upon the settings used. In general the higher the frequency/voltage and the tighter the timings, the lower you have to keep the temperatures. It is pretty easy to determine if you are temperature limited though, since you can confirm it with simply giving the modules some additional airflow. If it was a temperature issue, that would remove the instability.

A kit like that should be able to reach DDR4-3800 CL16 with less than 1.5V no problem, if your setup can handle it. At 1:1 (3800/1900) that is pretty close to optimal already, so there is no reason to push much more voltage into it. I would recommend staying under 1.5V, esp with 4x16GB packed tightly together and temperatures hitting mid sixties at 1.45V (which already is on the higher end).