I have my own opinion, both watzup_ken and Yongkit have your point. I strongly agree not to use PWM on pump. set it to a fix cycle. yes motor pump will not last but think about it.. Liquid AIO are never meant to last forever. Max Lifespend is about 5 years or so. For me I just run the pump at 100%. my Arctic liquid Freezer II 280 is running at that speed since year 2019 December till now.. no issues or whatsoever, but my Germany friend who gotten this AIO for me back then is also using this AIO (Anyway these two AIO were purchase at Germany IT Fair, buy one get one free lol) his broke down this year april and he just leave it as auto which fluctuates the pump cycle speed. Anyway these are Rev 01 AIOs. Rev 02 03 04 05 and 06, even they are connected or daisy chained on one connector. there are no rpm control on the pump, only the fans. if you dont believe you can try this. remove the fans from the splitter, connect to CPU_FAN1 and plug the pump at W_PUMP.. there will only be readings on the fan and not the pump, therefore the pump is running at full speed.