How much performance difference between vega 56 flashed undervolted/overclocked vs vega 64 overclocked/undervolted,both will be reference design 50 more then vega 64 used and 80 more then vega 56 used i can get rtx 2060 or rx 5600xt new,which should i get and is it true vega 64 reference design has bad cooling and unbearable noise,can this be solved after undervolting or not.