Honestly, there isn’t really a “max” that fits every card. It depends a lot on the GPU model, cooling, and your power setup. Most miners just push clocks slowly until it starts crashing or temps get too high, then back it off a bit. As long as you keep temps under control and don’t go crazy with voltage, it’s usually safe. The real danger is heat and running fans 24/7, that’s what kills parts over time.