Some news about Crosshair VIII + Ryzen 3900X + Bios3003 stability.
After some researches and experimentation i found that these settings makes my system fully stable without whea error or random resets:
FCLK=1866Mhz
MEM_LCK=3733Mhz
CPU_OFFSET_VOLTAGE = -0.025V
CPU_SOC_VOLTAGE= 1,025V
DRAM_VOLTAGE= 1,35V
VDDG_CCD= 0,95V
VDDG_IOD= 0,95V
CLDO_VDDP= 0,85V
1,8V_PLL=1,81V
PBO_ENHANCER= ENABLED
All other settings to AUTO.
This is CPU_Z validation with system specs and memory timings:
https://valid.x86.fr/dpzjs6