The game often crashes on multi-core processors. You should restrict the game to CPU 0 (single core) via Task Manager or the GPxPatch settings to prevent instability.
GP4 is famous for its detailed mechanical simulation. A good setup balances for corners and top speed for straights. Grand Prix 4
Since GP4 was released in 2002, it requires specific community tools to run smoothly on Windows 10/11 or even the Steam Deck. The game often crashes on multi-core processors
Set your 7th gear to be slightly longer than needed for top speed alone; this allows you to utilize the slipstream (draft) of another car without hitting the rev limiter. Grand Prix 4 (2002) F1 Car Setup Guide With Mark Hemsworth A good setup balances for corners and top
Adjust dampers and roll bars to manage how the car handles bumps and weight transfers. A common tip is to make one change at a time to quantify its impact.