I have an old (40 years- back when they were well made and h-e-a-v-y) Delta with 6" height and 18" width capacity. I use it to rough out curved braces from 4" stock frequently. When I inherited it from my dad (a tool and die maker) I foolishly replaced the three phase motor with a fairly HD single phase 120. It's not the fastest saw in the world, but it's not the slowest either..
Having said that, In my experience it's more about the blade you're using than the HP. A decent 4 tpi narrow re-saw blade with some set goes as fast as I want it to. Setting up in-feed and out feed tables help tons as well.