Vulkan API – Feedback, Known Issues, and FAQ

The problem is your graphics card....out of vram.....performance will be terrible as you have figured out. I can recreate this exact problem with high end hardware (Rtx 5070 12gb) if it uses more than 12gb terrible performance, yet using direct 3d mode doesn't have the same issue.

On the other hand vullkan is the only way to get maximum performance when you have top end hardware and are cpu bottlenecked

Example. 80-90fps in d3d mode



150fps in vulkan

 

Forgot to add its KDE and Wayland.
Anyway updating to Mesa 25.1.4, most of the screen flickering is gone, there is still some occasionally, mostly at the begginning after map loads, and then when driving around. Also, at least to me, before the flickering was white, now its black. Kinda weird. Also noticed that the new Mesa downgraded Vulkan version to 1.4.311, idk man.

Native linux version sadly still crashed even after recent hotfixes

 

Question for the Dev's about Vulkan and how it handles AI traffic. I'm well versed in how the game uses CPU cores/threads to process each vehicle spawned. Is vulkan starting to offload some of that work to the GPU instead of the CPU.

I ask because I've been doing lots of testing and found in scenarios where i'm obviously CPU limited when spawning 40+ cars, I'm seeing a FPS increase when using vulkan.

Example 1.

R9 7945HX3D 16 Core 32 Thread (Basically a 7950X3D but slightly lower power)
RTX 5070Ti
96GB DDR5-5200

Utah Map 40 cars spawned in D3D mode



Right around 60fps

Now in Vulkan Mode (All other settings the same)



Around 75fps, that's a decent increase in performance.

Example 2

285K 8 P-Core 16 E-cores
RTX 5070Ti
32GB DDR5-7200

East Coast USA 40 cars spawned in D3D mode



60-65 FPS

Then in Vulkan



70-75 FPS

So it seems like some of the traffic might be getting offloaded to the GPU?

Adding another curve ball

Example 3

285K
RTX 5090
32GB DDR5-7200

East Coast 40 cars spawned in Vulkan



85-90 FPS

I'm CPU limited with that many cars spawned, but simply adding a better (the best GPU) I'm now seeing an increase in performance.

So is this just a coincidence or is Vulkan being tweaked to allow the GPU to process traffic?

 

Going back through some of my older video captures, looks like it's been a thing for at least a year.

14900K RTX 3090 40 cars spawned.



14900K RTX 4090 40 cars spawned



That's a pretty big difference in performance with only a GPU change