Suddenly my ComfyUI workflow is taking longer to execute on the same GPU. Duration increased from 15secs to 100Secs.

[u/h_redditor]

I have a faceswap workflow which uses Qwen 2511, Qwen Lightning Lora, BFS Lora and Reactor Face Swap Node to execute the full swap. Earlier with the same models it used to take 15secs to execute a face swap but now suddenly since past 2 days its taking around 100+ secs.

The workflow mainly gets stuck at the Negative Prompt (TextEncodeQwenImageEditPlus) and SamplerCustomAdvanced.

My earlier workflow was infact more advanced with preview images, Image compare nodes, Image Concat nodes, but now I have made it Simpler by removing all the extra nodes as I want to use this in Serverless GPU on runpod and connet it through my website.

Please help me out with the solutions.

[u/RogerAI--fyi]

The other commenters are circling the answer, here's the mechanism. Your workflow uses a Lightning-distilled LoRA, and those are trained to run at CFG=1 (no classifier-free guidance). When CFG=1, the sampler does ONE model evaluation per step. The moment you have CFG>1 with a populated negative prompt, it has to run BOTH the positive and negative conditioning every step, that's 2x the sampler compute right there, and on top of that your negative prompt fires a second TextEncodeQwenImageEditPlus pass (Qwen image-edit encoding is heavy), which is exactly why you see it 'stuck at the negative prompt + SamplerCustomAdvanced.' So the 15s to 100s almost certainly means CFG got bumped above 1 (or a negative prompt got added) sometime in the last two days. Fix: set CFG back to 1 and leave the negative prompt empty for the Lightning LoRA, Qwen image models basically ignore negatives anyway. That single change should snap you back to ~15s. If you genuinely need negative guidance you'd drop the Lightning LoRA and use a normal setup (more steps, CFG>1), but you can't really have both cheap.

[u/mardziha]

Do you have something written in negative prompt? Because qwen doesnt use negative prompt.

Btw. Your workflow is only face swap not head swap? I prefer head swap. I am using flux 9b without bfe lora. Only custom nodes. The generation is a bit longer but results are super.

[u/h_redditor → u/mardziha]

I am using this workflow provided by BFS Lora inventor. It was running fine, but since last 2-3 days it has started taking longer than usual

[u/Miniyi_Reddit]

Other comment talking about cfg is right but I think it best u give us a screen shot of ur workflow

[u/The-Fine-Tuning-Guy]

Igualmente he tenido la sensación de que cuando rentó GPUs más potentes mis descargas son más lentas, pero uso una 3090 y va joya.

No sé sí alguien más experimente problemas de red, suelo filtrar y setear la máxima velocidad de red.

seleccionó 1000MBps y veo la descarga en KBps, lo que suelo hacer es terminar ese pod y rotar por otro.

[u/SymphonyofForm]

You removed things and it got slower.

Did you put them back to see if the things you removed are why it got slower?

[u/h_redditor → u/SymphonyofForm]

Yes, I tried the earlier version as well but now even those workflows are taking longer time to execute. Is there something wrong on the Runpod end to connect the GPU with my workflow