Stable diffusion only using half of GPU processing power

I Have been using Stable Diffusion (automatic1111) for a while but when I upgraded to automatic1111 1.8.0 I noticed a massive slowdown in generation times. I tried updating pytorch and xformers but that did not help.

After downgrading to automatic1111 1.7.0 and resetting my pytorch and xformers to the old version the problem persisted.

I noticed that the Python instance for Stable Diffusion is only using about 40% of my GPU processing power (when it used to be a consistent 100%).

This is on an SDXL model without maxing out the VRAM (9.5 out of 12 gb) (CPU hovers around 20% utilisation).

I have tried deleting the venv folder and letting Stable Diffusion reinstall it from scratch, but no luck.

I am using an RTX 3080ti.

Any help would be most appreciated.