[Bug] Z-Image render time

[daxime]

Git commit

master-390-edf2cb3

Operating System & Version

Ubuntu 24.04.3

GGML backends

Vulkan

Command-line arguments used

./sd --diffusion-model ./models/z_image_turbo-Q5_0.gguf --vae ./models/ae.sft --llm ./models/Qwen3-4B-Instruct-2507-Q4_K_M.gguf -v -p "a mix of anime and 3D style, a beautiful girl, perfect face, detailed face, walking in cyberpunk city at night, futuristic dress that emite light, intricate details, luxurious background, neon glow, highly detailed, 4K, professional photographie" --seed -1 --steps 9 --cfg-scale 1.0 --offload-to-cpu --diffusion-fa -H 512 -W 768

Steps to reproduce

It is random.

What you expected to happen

8 to 9s/it

What actually happened

Sometime, it goes up to 50s/it. And if launch the exact same command, it go back to 8 to 9s/it

Logs / error messages / stack trace

No response

Additional context / environment details

No response

[wbruna]

Sometime, it goes up to 50s/it. And if launch the exact same command, it go back to 8 to 9s/it

Are you low on VRAM? Memory pressure could cause this (see ggml-org/llama.cpp#17605 for details, and a possible workaround).

[daxime]

I have 8Gb or VRAM.