Fastest point-plane distance in $R^3$

Question

Many questions regard computing the point-plane distance, my question in borderline with computer science, though.

What is the fastest way of computing in $R^3$ the point-plane distance, with the plane identified by three points?

I will try to define "fast" in two possible ways:

• as in counting each floating point operation
• as in counting each SSE operation (or similar vectorial facility),

with each operation taking the same amount of time (which is not realistic, but allowed in some computational models).

Thanks!