He's saying the opposite tho. That's a general problem in this forum, people don't read the questions properly and I've made that mistake as well. Also careful with that OC in your sig. You might degrade the CPU.
To the OP, you probably kept HDD cleaner to make it faster since it's a very slow device, and that might have resulted in lower CPU usage. Or even simpler, your power options in HDD are different. It has to be software related.