ComfyUI user weighs zram weight offloading: zstd decompression may bottleneck the inference hot path

Agreeable_Return2632 · reddit · 2026-09-27

A user running MiniMax H3 in ComfyUI with CPU offload (i5-14400 + RTX 4070 + 32GB RAM) considers zram to extend usable memory for offloaded layers. Rough math suggests zstd gives only 1.3-1.4x compression on near-random-entropy fp16 weights, adding 10-15GB effective capacity.

The catch, which the author flags themselves: offloaded layers are read on every forward pass, so decompression runs continuously in the hot path — RAM bandwidth is 35-50GB/s while zstd decompression tops out around 5-10GB/s even parallelized. They ask whether anyone has actually benchmarked zram for weight offloading in inference pipelines.

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