My i7 6700 is running at 70°C when I am playing RCT Deluxe, on win10. I never encounter this issue with other old games on GoG.

I play RCT in 800x600 fullscreen. I tried windowed mod without sucess. Do you have any idea ?

Why not use OpenRCT2 instead?

Because it does not work, it fail to find a "g1.dat" file in the RCTD directory.

Well, yeah. It's based on RCT2, which I would presume you'd also have. You can import the data from RTC1 into OpenRCT2 as long as you start with RCT2.

Problem "solved" by purchasing RCT2 and playing with OpenRCT2. And this tool is just amazing.

It isn't a tool, it's an entire reimplimentation of the game engine.