slow response time during editing

I am editing a score and experience very slow respons time.
I use standard PC-keyboard to generate music (notes and lyric).
But somtimes (specially when the score is getting large) the response time is so slow that all the fun is gone.
For instance I have to wait several seconds to move to the next word when I am generating lyric.
Very annoying.

Is there a way around this?
Anything I can do to speed up the process?