6-Pin GFX_12V1 on X399 Taichi?

[RyanTScott]

Is it nessescary to connect the 6-pin GFX_12V1 when using 4 GPUs on the x399 Taichi?

 

[kanewolf]

What does the user's manual say? "Install the PSU’s power cable to this connector when 4 graphics cards are installed." PDF page 27 ...
The manufacturer says "YES".