How should I update to increate machine CPU usage?

one machine which request service.

param: 30000QPS run 180s
report: (actual: 18181QPS run 296s, the machine CPU use 40%)

param: 20000QPS run 180s
report: (actual: 19889QPS run 180s, the machine CPU use 10%, this is my wish)

So, I want the machine CPU used 90%+, and QPS and during time which also is my wish.

How should I do? thanks!