I have an old xspc vario d5 that I used to run without the pwm at the setting I put it to on the base of the pump. Depends on the make and model of the pump. I know my Alphacool D5 runs at 100% without the PWM plug, but at present I run the 1080 and a 480 Monsta off my D5 Next in my case. I picked up a cheap Arctic Fan hub, and ran the fans into that, and then a 4 Pin Pwm extension back to my Pc case and D5 pump so I can control the fan speeds via Aquasuite