The warning "Num samples per thread reduced to 32768, rendering might be slower" typically occurs in V-Ray or similar GPU-accelerated renderers when your scene is reaching the memory (VRAM) ceiling of your graphics card. Why This Happens
Each thread processes a batch of samples for a specific region of the image. The "num samples per thread" refers to how many samples that thread will handle before it stops or synchronizes with others. The warning "Num samples per thread reduced to
Memory Ceiling: The renderer is attempting to load everything into video memory to perform the render, but the scene's data exceeds what your hardware can handle. The warning "Num samples per thread reduced to
Solution: Use the Optimizing Memory Usage Guide from Chaos Support to reduce scene heavy-hitters. The warning "Num samples per thread reduced to