Human Pose Estimation runs with either a single-pose or multi-pose detection algorithm. The single person pose detector is faster and more accurate.
The multi-person pose estimation algorithm can estimate many poses/persons in an image. It is more complex and slightly slower than the single-pose algorithm, but it has the advantage that if multiple people appear in a picture, their detected keypoints are less likely to be associated with the wrong pose.
The output & input resolution have the largest effects on accuracy/speed. A higher output stride results in lower accuracy but higher speed. A higher image scale factor results in higher accuracy but lower speed.