hello after 2h on unigine valley i have a score of 3640
my configuration air cooling : gpu clock - memory clock
                                       .    2162mhz - 4657 mhz
 
switch master - t 54°c - fan 65% - v1.0930 (+112 ) - gpu clock +171 - memory clock +654 kboost enable
so 1778mhz-2329mhz- boost 1968mhz
No crash no artefact
I have more to test in games over a long game

 
edit ; but not stable in game  ...( assassin Creed origine benck )
 
 
edit 2 :    2164mhz-4551mhz
 
no crash , no lag  , no artefact with volatage +122 ( switch slave ) +159 to gpu and +548 to memory on assassin creed origine benck
on valley  score 3472 - 83fps ( stock )
                       3766 -90fps  (oc+kboost)
on games the difference is minimal or insignificant ...