Ok.
Have you also tried to set a bigger pagefile in windows ?
Just found this - you can try it maybe :
-lidag low intensity mode for DAG generation, it can help with OC or weak PSU. Supported values are 0, 1, 2, 3, more value means lower intensity. Example: "-lidag 1". You can also specify values for every card, for example "-lidag 1,0,3". Default value is "0" (no low intensity for DAG generation).