Ah! In our experience, homeschooling makes things easier with a fast input/slow output kid.

Before I saw his test scores and realized that DS's processing speed was significantly lower than his "thinking speed" (if you will), I was pretty impatient with him, just as his public school teachers had been. Once I realized that this was not dawdling, but that slow output was part of his nature, I allowed more time and was less cranky about how long he took to do things. We both got a lot happier!
On the bright side, he seems to be getting faster as he gets older. I'm not sure if this is a function of age or practice or what, but he seems to get through a lot more material than he did last year--I mean a lot more! Perhaps you'll see something similar?