!! BIG GPU problem !! big slowdown when rendering animation

V-Ray V-Ray GPU Issues
1

Hi,

I want to render scene using GPU. One image took about 7 minutes. BUT when I render animation, two frames render 7 minutes each and third render 30 minutes! It makes no sense because image looks almost the same. So I cancel it and render third image alone. And it took 7 minutes.
I cant render the animation because of this problem. What I can try to fix this?
Thank you.

2

I probably fix this issue. I install newest VRay nightly 61003 and new nvidia game driver instead of studio driver. Seems one or both fix this issue.