I have a 12300 (ES) on my apex encore that gets stuck at post code 55. Works fine with any other CPU. Do i need a special bios or ME for this to work? This CPU previously worked fine on a z690 aqua.
Lower voltage and CPU clocks to prevent downclocking, and achieve a better overall clockspeed and you'll get a better result. I'm currently #5 @6.1/4.9/5.4 ratios.