Hi thanks for choosing Dell. From what I think it looks like if you want to go a lot less than what's close to 100% you will need to change to a better controller (hardware replacement). I wouldn't say it's broken, it's just a lot of I/O there, but if you wish to have your controller logs checked, please reach out to the local phone support with the system's service tag. Have a good one!
i have a perc h700 and it will go to 100% under the slightest load i have 4 2tb sas drives 7.2rpm 
perc h700 100% usage