Warning Num Samples Per Thread Reduced To 32768 Rendering Might Be Slower -

If you have set your global samples to an extremely high number (e.g., 64k or higher) without using Adaptive Sampling, the engine may attempt to push too much data through a single thread.

objects, which generate massive amounts of geometry at render time. Clean Up Render Elements : Remove any Render Elements

Often, users set their Max Samples to 0 (infinity) or a placeholder like 100,000, relying on a "Noise Threshold" to stop the render. If the Noise Threshold is set too low, the engine will try to reach that 100k sample count, triggering the 32k thread cap. Try setting a more realistic Max Sample limit (between 4,096 and 16,384 is usually plenty for modern denoising). If you have set your global samples to

A denoised image at 2,048 samples usually looks identical to an un-denoised image at 32,000 samples but renders in a fraction of the time. Enable Adaptive Sampling

I can provide the specific menu paths or "User Options" code for your exact setup. Share public link If the Noise Threshold is set too low,

Try disabling displacement in the Global Swatches settings to see if performance improves.

: When in doubt, run a benchmark with and without the warning. Measure actual render time for your specific scene. Often, the difference is smaller than you’d expect. Enable Adaptive Sampling I can provide the specific

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).

Reducing samples per thread means the GPU does more frequent, smaller tasks rather than fewer, larger ones, which can lead to increased overhead and slower rendering times .

The rendering engine attempts to allocate enough memory to handle a specific number of samples per thread for maximum efficiency. If your (Video RAM) is full, the engine "shrinks" these sample batches to fit into the remaining available space.