System Information
Operating system:Windows 10
Graphics card: 1x Nvidia RTX 2080 Ti

Blender Version
Broken: Blender 2.82a
Worked: every previous version

When I render on Optix sometimes (50% times) rendering goes extremely slow after rendering the first tile of render

This is happening to me only on hudge scenes like 1,44GB. And this is not happening every time but quite often ( 50% of times )
To Explain that let's just assume that we have an interior scene which has nothing special in it ( I know that optix is not working with AO shader and branched path tracing)

1. I hit render and first tile is rendering really fast and when I'm checking how my card is vorking cuda usage looks like this:

2. But after rendering first tile, second goest extremely slow and my cuda usage looks like this

and expected time of rendering goes from 1 hour up to 15 hours or even 20 hours

I know that you might say that not every tile is rendering with the same speed but that is not an issue. When I restart PC or sometimes when I restart blender or sometimes when I prerender scene for something like 1 minute with material override option enabled render goes in the correct way. What I mean by that is that:

1. I hit render (same camera same samples and all other settings)
2. Render goes with almost same fast speed on every tile and full render is acomplished after 1 hour. My cuda usage looks like this:

As I wrote before this happens to me only on complicated hudge scenes but my work consits only those type of scenes ( I'm interior designer)
I have this problem since the first release of blender with optix rendering. I,ve also checked tenperatures on my GPU and nothing goes above 66 degrees.
Here is my file but it is quite large 1,44 GB:

For me it is hude deal if my render goes 1 hour or 15 hours so pls help me :)