Huge frame drop in PCars 2

[PEagle]

The title says a lot of it.

I run almost the lowest settings and use an HTC Vive.

My config: 

i7 4790K @4.7GHZ 1.32V

GTX 1070 @1860MHz memory @8008MHz

 

I thought it was CPU bottlenecking but I extracted data with HWinfo64 and here is what I have (extract of the 1.5+ hour session):

I left the game around 16:37:55 and had a massive lag at 16:37:47 (I suppose, time to push the button and my clock said 16:38).

 

Any idea why this happens? 

 

I collected more data that I can put on that graph if needed.