Please check if turbo hand grabber is ticked(ticked is faster)
please check if you are using only one Thread. in one thread mode it only uses 10% cpu. please use atleast 2 (recommend using max allowed).
You can find both of them in File-Settings.
Please also note the following points
You need to defrag your hard disk once a week. If you want a free option i recommend Defraggler and paid option I recommend o&o
you can just google them both.
You also need to do a complete maintenance of your database once a week.
Finally remember NC as the HM app uses more definitions and they are more intense since HM2 can display things HM1 can't (spark graphs, partitions etc). Please dont compare hm1 speeds with hm2 for NC