You asked the same question I've been asking (with no answer)
No one says which parameter is used in the PWM function.
If, when choosing the PWM function, the coolers are at maximum speed, it indicates high temperature of your CPU by the defaults (??) of the HWi32 monitoring software (click on the thermaltake board info), I guess.
To make the coolers run at a slower speed, just uncheck the PWM function