If you are using Scrambling Distance to speed up previews, a value that is too aggressive can trigger memory warnings.
: When V-Ray realizes it cannot allocate enough memory for its default streaming buffers, it scales down the block size. It forces the hardware down to a hard floor of 32,768 samples per thread to prevent an outright out-of-memory (OOM) crash.
This is for production; it’s a debugging tool.
Use the Optimizing Memory Usage Guide from Chaos Support to reduce scene heavy-hitters.
The loss is worse when:
The warning notes that rendering "might be slower." This sounds counterintuitive—shouldn't fewer samples be faster? In this context, "slower" refers to efficiency
In most other cases, you can safely ignore the message. Many production studios render with this warning every day without noticeable downside. However, if you are rendering animations with hundreds of frames, a 10% slowdown adds up – that’s when you should apply the fixes above.
The software limits how many data samples (e.g., pixels, rays, sound samples) each CPU/GPU thread can handle at once. The limit was lowered to 32,768 — probably because of hardware constraints (e.g., low memory per core, or driver-enforced safety).
: The scene (geometry, textures, and light cache) is larger than your GPU's total video memory. High Resolution If you are using Scrambling Distance to speed
A pause. “Eighty percent.”
You can track exactly how much memory is being used with tools like GPU-Z to verify if you are hitting the hardware's ceiling.
On a technical level, the number 32,768 is a known limit for some GPU resources. For example, on many CUDA‑capable GPUs, . While the sample‑per‑thread cap is not directly the same as register count, both point to a hardware boundary where the rendering engine has to scale back its work distribution to stay within the physical limits of the GPU.
Instead of pushing samples into the stratosphere, use a denoiser (like NVIDIA AI or Intel Open Image) to clean up the final bits of grain. Conclusion The "32768" warning is your renderer's way of saying, "I'm working harder, not smarter." This is for production; it’s a debugging tool
The warning is your system’s way of saying, “I’ve run out of video memory, so I’m falling back to a safety mode that will be much slower.” It is most commonly seen in V‑Ray for SketchUp during high‑resolution renders or long animation sequences, but it can occur in any GPU renderer.
: Older GPUs or those with less VRAM/lower compute capabilities hit this limit much faster than modern RTX cards. How to Fix and Optimize Performance 1. Adjust Sampling Strategy
Use instancing for repetitive objects (like trees or furniture) instead of importing unique meshes. 3. Manage VRAM
| Hardware / Scenario | Estimated Performance Loss | |---------------------|----------------------------| | High-end GPU (RTX 4090, 24GB VRAM) | 3–8% (barely noticeable) | | Mid-range GPU (RTX 3060, 12GB VRAM) | 8–15% (perceptible) | | Low-end GPU (GTX 1650, 4GB VRAM) | 15–30% (very noticeable) | | Integrated GPU (AMD Radeon Vega) | 25–40% (severe) | In this context, "slower" refers to efficiency In