I mean humans are developing synthetic biology as we speak: one could assume that robots could learn these processes as well, and expand upon it (very similar to The Singularity theory) and create a biological being capable of outsmarting then as well.
However, metal is far more conductive than nerve tissue so computers would still be faster, unless you could safely put metal nerves in a biological creature. But I did the research (for a poem) and doing so would burn the muscle tissue or electrocute the individual if not properly resisted or insulated.
—Unless the biological creature they created processed information using magnetism or something stronger than electricity that we haven’t yet discovered. Chances are robots and cyborgs will most likely develop faster. The hard part is teaching them creativity and independent thought.