stano de Posted yesterday at 11:35 AM Posted yesterday at 11:35 AM Problem Title: Game freezing (AppHangB1) on RTX 4070 after update – temporary fix by forcing DX11. Message for Developers: Hello, I would like to bring to your attention a persistent software stability issue in SimRail following the recent October update. This issue causes the game process to completely freeze, logging system error codes 20a3 and 7651 along with an AppHangB1 event. By default, when launched normally via Steam, the game automatically boots using the DirectX 12 graphical API. However, this interface currently exhibits a severe conflict regarding resource allocation and workload distribution between the CPU (Intel Core i9-11900KF) and the GPU (NVIDIA GeForce RTX 4070). As a result, the Unity game engine gets stuck in an infinite loop directly within the RAM, causing the screen to freeze entirely. Furthermore, Steam does not provide any built-in launch pop-up menu to select an alternative renderer. A 100% functional workaround is to manually force the older DirectX 11 API by adding the -dx11 parameter into the Steam Launch Options. After switching to the DirectX 11 interface, memory management and graphical thread processing become significantly more stable compared to version 12. The hardware workload distribution runs flawlessly, and the game operates completely smoothly without any crashes or freezes. It would be highly appreciated if you could add a separate launch option in Steam allowing players to choose between DirectX 12 and the more stable DirectX 11 interface, or optimize memory management under DX12 for the newer Ada Lovelace GPU architectures. Thank you.
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