This post works as a kind of message for all people having the same problem.

I bought the game yesterday. Today i was able to install it (21 GB) and started to play.

I started the game and the first 15-30 minutes i was still creating characters, when suddenly the screens went black, music was still playing in the backround, the grafic card ventilation went into panic modus (very loud) and i was not able to do anything any more.

I rebooted and after it i had to learn, that now the system was ...messy. MSi afterburner, which i really really need to be able to play without having to deal with a very loud computer was not working anymore. I use two monitors, and have different files on each on them. One monitor screen was not shown anymore, so i could not access the files stored there.

I reset the windows system back to an older time, when everything was still working. Then i uninstalled and reinstalled the game. During that time i tried to figure out, what had causing this and found an forum, where some guy were able to track the problem back to issues related to the unity engine.
(The core and memory clock of the grafic card does interfear with the used clocks of the game.)

I will now start the game again.
If it breaks down again, i will turn the clocks down to the lower base clock numbers.
If the game works as it should without crashing down, i will post this, too.

Edit: Ok, after having played for one hour, nothing happend any more. Lets see, if it still continues to work in the future.