The only high tech/low construction center is the San Francisco Bay area. Seattle has had a lot of construction over the past few years. Since housing supply isn't perfectly elastic, it can take a few years before supply shifts to meet demand and in the mean time, prices rise. New York is definitely a high tech center but it is also a center for a lot of other things too. I'm not sure if it is high or low construction but there are other factors at play in the high rents there that aren't at play in other tech centers.