Blank GPU render and fireflies

I’m currently modeling/rendering a Lamborghini Aventador and with the car paint reflections and high res hdri it’s a bit cpu intensive and time consuming to render so I switched to GPU rendering, however, when I start the render it finishes in a couple of seconds with the plain alpha bg but if I use GPU rendering in the preview render it works fine. Problem number 2: After the cpu render finishes it is riddled with fireflies, I let the render go all the way to 1500 samples in the viewport and 500 samples full rendered with the cpu and the fireflies are still present. Please help! I am using to Nvidia 765m. I have tried enabling and disabling caustics to no avail.
Here is a photo of the fireflies:


Hi @UKNOWHO. About your problems:

  1. That is caused by the memory of your Graphic Card. If it has not memory enough, the render finishes showing a black screen.
  2. You can try to use the clamp option to fix the fireflies. It is in Properties panel >> Render Button >> Sampling Panel. Start using a value of 9.0

That worked, thank you!