No that is actually very important.. (simple terms) ..AC is telling you it requires more, but your system had no more to give, you are lucky it did crash.
To be honest with you 19 drivers @ Bathurst is about right, anymore will tax a lower spec machine.
Okayama is better optimized, so will not trouble you so much.
One other method I do ..you or may not be aware of it ....when game is running ALT TAB out ..right click bottom of your desktop and run " Task Manager" Find AC (top of list or near top) right click it and Set Priority = Real Time ..your system will now look after AC a lot better