Have you tried single processor affinity?
I have already set affinity to one core as default. Does not matter.
Still, thanks for trying to help. Suddenly, the ONE game that is not running (I-War) has turned into the ONE game I want to play, out of all the one's, I have installed recently.
[EDIT] (for those, who might stumble over A) this issue and B) look for a solution:
To my surprise, the game RUNS PASSED THE LAGRANGE CRASH(!) ON LINUX WITH WINE!
Instead an instant crash, you now get a short in-game ship 'flash' effect before and after jumping through "Hyperspace". In between the short (Bink) video runs just fine.
The game on Linux/WINE also runs with the nGlide Wrapper on my 1080p screen (I just copy-pasted the Windows 10 installation of I-War to my Linux drive, with the nGlide Wrapper and Glide dlls already in the game root folder. No fuss.
I just played it several times. "Hyperjumps" work now and I was able to get passed the "Adv Navigation" tutorial mission.
FInally, I can play the game, I missed out on, when it came out!
Ubuntu 18.04.1 LTS
GOG version of I-War