perhaps you should read again too. The commentary on better performance when lenses switched was on AF accuracy. but for AF speed, the dpreview comments are extracted below.
"I was impressed with both cameras' performance in low light. As I mentioned, I got better autofocus in low light from the α7R, but image quality from both was very good in low light, such that I had no trouble letting the camera's ISO rise to 6400."
"After shooting with the α7 and α7R for some time, I preferred the α7R for its faster, more reliable autofocus and better images overall. Naturally, I wanted to prefer the α7, with its lower-res 24MP sensor and lower price."
Micro-lense wise i can't comment much anyway. shall test it myself on saturday using a CV 15mm 4.5.