Yes, Houston is known for their quick processing times. Where I am it seems they take an average of 6 months to about 9 months. Washington, D.C is just as busy, if not busier, than NYC. I'm hoping it goes faster but I'm not really holding my breath.
Have you really checked because USCIS has improved in most cities. But I know Houston, Dallas, Atlanta, and some part of New York have between 2.5 to 3 months average processing time if the case is straight forward.
Are you using the processing time tool on USCIS website? That is not really accurate....it doesn't tell the practical time. Try to look at recent filers in your region who just completed the process.