Is GHz really matters in playing computer games?

Hello to u all.I wanted to ask that is GHz really matters in playing games on my laptop.It got 1.73GHz (Dual-Core).Can't I play games which requires 2.4GHz on it.I've got 384MB graphic card , 2 GB RAM and 1.73GHz.I've got XP as my operating system.Pls also suggest some games which u think are best and can run in these specification.Pls help me bcs I really wanna know the ans.Pls help me.