May be need to enable 8gb solver for vega 64 ?
Thats odd... is this 0.9 or 0.9.1? Please check!
I ask because even the 0.9.1 4G solver should be much quicker.
If its 0.9: then the 8G does not load because the Binary Kernel can not be loaded --> install Adrenalin 19.10.1 or newer in Windows or 19.30 in Linux. Also upgrade to 0.9.1, pool hash is better with that one.