I haven't noticed having this problem. As far as I can tell, my Hubpage emails are on time. You may want to clean out your "cache". That can help to speed things up. I would say that because your twitter alerts are slow, it's most likely either your computer or yahoo email.
Also, you might want to run a security check for viruses. It's been my experience that if I have a viruse, it slows and fouls up everything!
I wish you good luck and I sincerely hope that my answer has been useful for you.