Problems about rendering with vega64

Hi guys, as the title suggested, I’ve a display card issue.
recently, I got myself a new vega64(2nd hand) to replace my 1080 as I heard that vega64 has a better performance.

But the thing is after i installed my vega64 and vega driver, I tried to render things by cycles. the result was unacceptable,my vega 64 perform so badly and the rendering time was just doubled compared to 1080.

I tried to overclock it but it will crush frequently and I even update the power supply to 850W.
so, is my card broken or i installed it wrongly??

I heard, but idk if it is good diagnosis, that with all vegas was/is problem with drivers: if you downloaded newest card driver can even crash (black monitor display, only action to do is restar your compuer from power button) try to find older drivers, for example from feb 2019.

I have a AMD Radeon Pro Duo Polaris. I can tell you the AMD drivers are a huge problem. The Pro Duo is very finicky with the drivers so I would expect the same for the Vega GPUs. At least for the Pro Duo, I can not use the latest drivers, even though the AMD site says you can. It is just not true. I had to install and uninstall drivers until I found one that would not behave abnormally. It was a huge pain in the you know what.

Oh that would be so time-consuming. But is really Vega better in rendering than 1080? If not, I think I will just re-sell it.

I googled the vega64’s driver, most of the people said that’s doing better and better now. It seems amd’s display card still can’t compare with Nvidia.