Thanks @logicus. I tried before to increase my HBM speed higher than 960MHz but it always give me BSOD. Is this because I didn't flashed my card with Vega 64 BIOS?
Yes, because cards have original bios.I flashed my card with Vega 64 BIOS.
what cooling you have for rig, what is the temperature core and HBM of the cards, and RPM?
Air cooling /open rig/ , 55 core temperature and 65 HBM temperature of the cards, and vga fan - auto /~3500 RPM/