Warning: Num Samples Per Thread Reduced to 32768 - Rendering Might Be Slower
However, Windows and Linux drivers, as well as the NVIDIA CUDA architecture, have limits on how much work a single kernel execution can handle before it risks a TDR (Timeout Detection and Recovery) event—where the OS thinks the GPU has frozen and restarts the driver. To prevent a crash, the rendering engine automatically caps the samples per thread to 32,768. Why Rendering Might Be Slower
Note: This may reduce peak performance, but can eliminate the warning and improve stability. Warning: Num Samples Per Thread Reduced to 32768
The second half of the warning is the most frustrating: "rendering might be slower."
Best practices to avoid the warning
The warning " Num samples per thread reduced to 32768, rendering might be slower " is a critical notification typically found in or other CUDA/RTX-based rendering logs. It
signals: void configChanged(); void warningTriggered(QString message);Additional resources
The Specific Number - 32768: The number 32768 seems arbitrary at first glance but recognizing it as (2^15) can provide insight. It's a power of 2, which is often a significant number in computing as it aligns with binary counting and the common word sizes in computing (e.g., 16-bit, 32-bit).