Yup, with a 1090T already in there there's not much point in getting a FX-8150. It is essentially a sideways move; you probably won't notice any real-world difference in performance.
If you need more CPU horsepower, your choice at this point is to either wait and see what AMD releases in the future for Socket AM3+, or get a new motherboard and go Intel.
The years just pass like trains. I wave, but they don't slow down.
-- Steven Wilson