NVIDIA Prime not achieving maximum performance

Graphics / Linux Linux
1

When I use nvidia-prime (__NV_PRIME_RENDER_OFFLOAD=1 __VK_LAYER_NV_optimus=NVIDIA_only __GLX_VENDOR_LIBRARY_NAME=nvidia), it only gives me about 6k FPS compared to using solely NVIDIA to render everything (20k FPS), I’ve read somewhere that high FPS counts do not matter, and that I should try running a benchmark, so I did (Minecraft). I got 60 FPS, but it sometimes drops down to 40 FPS and there’s severe screen tearing. I checked nvtop and it says that the GPU is running at 50% usage, at 500 MHz (supposed to be 1097). I ran glxgears and it was still 50% usage, but the clock speed is at 1097, which is correct. No matter what I try, it’s always around 50% usage, sometimes reaching up to 75%. There’s basically nothing I can do in nvidia-settings because I am using the iGPU and PowerMizer isn’t there.

nvidia-smi shows that its at P0, and no throttles are active.
i use arch btw, GTX 860M 2GB, i7-4710HQ, 2x8GB DDR3.

nvidia-bug-report.log.gz (342.3 KB)

2

Seems like I had optimus-manager installed, and I had to switch to “hybrid” mode, NOT “integrated”/“intel” mode. Now it seems like the only bottleneck is my RAM (DDR3), I used dd + tmpfs and I got about 3.5 GB/s bandwidth, and that seems to be exactly what my card is outputting (200 MB/s RX, 3.15 GB/s TX), since PRIME render offload copies the frames from the GPU’s GDDR5 memory to the iGPU’s (system’s) DDR3 memory.