Lower your voltage to 900mV for both core and memory. I had 2130MHz stable mem with a RX574 (Samsung mem) and less than 900mV. I lowered the speed to 2100MHz only because of the fans noise.
For the core, @1150MHz, the same GPU (Gigabyte gaming) only needed 850mV.
i cant because of bios mod need that voltage, if i undervolt it will drop the hashrate a lot
You should reconsider that mod - 31-32 ethash is doable w/ a simple strap update for samsung/micron at 900mv or less. 1150mv is extreme overkill for any algorithm.