Why does the Witcher 2 Extreme Flora Mod give me Low GPU Utilization?

[tential]

4770k and HD7950. CPU is fine, GPU won't utilize with mod on. Just goes to around 69% and FPS tanks when overlooking any scenery when it should be working its hardest then.

 

[Carfax83]

4770k and HD7950. CPU is fine, GPU won't utilize with mod on. Just goes to around 69% and FPS tanks when overlooking any scenery when it should be working its hardest then.

CPU bottleneck due to the API if I had to guess. DX9 is a single threaded renderer with high CPU overhead.. Those two qualities don't endear themselves to higher detail levels.

 

[tential]

CPU bottleneck due to the API if I had to guess. DX9 is a single threaded renderer with high CPU overhead.. Those two qualities don't endear themselves to higher detail levels.

wouldn't i see a cpu thread pegged at 100% then?

 

[Carfax83]

wouldn't i see a cpu thread pegged at 100% then?

One CPU thread should have much higher utilization than the others, but I don't know if it will be pegged or not. If it's creating too much overhead for a single thread, then the thread would likely just stall, causing the GPU usage to plummet.

On a single thread, you'll have the game code running, the driver, the API, the kernel. Sort of like this, but worse since this image is showing DX11 compared to DX12. DX9 was really a mess, and I'm happy that developers have finally started abandoning it..

BTW, if you're running an AMD GPU, then driver overhead is likely to be even worse than if you were running a comparative NVidia GPU..