comfyui can not use multi gpu device ,only use one gpu device

### Custom Node Testing

- [x] I have tried disabling custom nodes and the issue persists (see [how to disable custom nodes](https://docs.comfy.org/troubleshooting/custom-node-issues#step-1%3A-test-with-all-custom-nodes-disabled) if you need help)

### Expected Behavior

comfyui can not use multi gpu device ,only use one gpu device
my computer have three rtx 4090 gpu device, but comfyui only use one, my workflow run need about 36G vram, why comfyui don't use another gpu device ?

### Actual Behavior

comfyui can not use multi gpu device ,only use one gpu device
my computer have three rtx 4090 gpu device, but comfyui only use one, my workflow run need about 36G vram, why comfyui don't use another gpu device ?

### Steps to Reproduce

comfyui can not use multi gpu device ,only use one gpu device
my computer have three rtx 4090 gpu device, but comfyui only use one, my workflow run need about 36G vram, why comfyui don't use another gpu device ?

### Debug Logs

```powershell
comfyui can not use multi gpu device ,only use one gpu device
my computer have three rtx 4090 gpu device, but comfyui only use one, my workflow run need about 36G vram, why comfyui don't use another gpu device ?
```

### Other

comfyui can not use multi gpu device ,only use one gpu device
my computer have three rtx 4090 gpu device, but comfyui only use one, my workflow run need about 36G vram, why comfyui don't use another gpu device ?