6x1060 gtx - problem with GPU CLOCK

[Malbo]

Hello,
I don't know why but i have 2 GPUs who won't go in "boost" mod, look at the pic:


https://tof.cx/images/2017/05/25/637b897ef2792627b91b191847897ce7.jpg
that gpu is under in term of gpu clock...


https://tof.cx/images/2017/05/25/07c600ade84fd1376888c97bbdf41e83.jpg
this one is ok.

someone have an idea ? i'm missing like 10-15% of performance for the GPU...

these gpu who won't boost seem to be hotter than the others GPUs, don't know why but they have 5°c more than the other (it is not a placement issue).



Thanks!