Thanks for your help with this, much appreciated.
I have a Fractal Design Ion Gold 550W Modular 80+ Gold. It's much more powerful than I wanted, and I know this will cause issues with efficiency, but I wanted to leave some room to grow incase I decide to use VMs in future (with a dGPU for example). Also has lots of sata connectors for future drives.
I'm currently only using the USB 2.0 ports on the back on my tower. Is it worth disabling the other USB controller? Is that even possible?
I already have the Intel driver, I believe, and can see the iGPU is in RC6 in powertop over 99.5% of the time.