Model Memory Usage Factor Override(ModelMemoryUsageFactorOverride)

The Model Memory Usage Factor Override node implements its functionality by cloning the input model and adding a wrapper to it.

The Model Memory Usage Factor Override node is an experimental tool used to dynamically adjust the model's memory usage factor during the sampling process. Its core function is to override the model's original memory usage strategy, allowing users to fine-tune it based on hardware conditions or performance requirements to optimize VRAM usage.

Node Functionality

This node implements its functionality by cloning the input model and adding a wrapper to it. This wrapper intervenes during the sampling preparation phase (PREPARE_SAMPLING), applying the user-specified memory_usage_factor value to the model, thereby overriding its internal default memory usage factor. Its internal implementation involves potential adjustments to the model's forward propagation process (such as the wan_ffn_chunked_forward method) to control the chunking strategy of tensors during computation, which in turn affects peak VRAM usage.

Node Parameter Description - Model Memory Usage Factor Override

Connection Inputs (Inputs)

Control Parameters (Parameters)

Output

Usage Scenarios

When you are processing high-resolution images or complex models and encounter Out of Memory (OOM) errors, you can insert this node between the Load Checkpoint node and the KSampler node. By appropriately reducing the value of memory_usage_factor (e.g., setting it to 0.8), you can attempt to reduce the VRAM required for a single computation, thereby completing the generation task with limited GPU memory.

Notes

This node is marked as experimental (EXPERIMENTAL). Its behavior and effects may vary depending on different model architectures or ComfyUI versions. Adjusting the memory usage factor may affect generation speed and, at extreme values, could even lead to degraded image quality or computational errors. It is recommended to validate the results after making adjustments.

Model Memory Usage Factor Override Node Source Code Link

The Model Memory Usage Factor Override node is from the ComfyUI-KJNodes node package.