Ok so I just realised the GPUs aren't taking the OverdriveNtool settings apart from fan speed and memory clock. Core clock does whatever the fvck they want and so do the voltages. HWinfo64 shows 1.25V on the memory despite me having set it at 900mV...
I think I'm going to give Wattman a go 
how did you manage to get hwinfo to work?
i'm using the 5.58 version on several PCs and most of them freezes my systems and causes 1 or more GPUs to "disconnect", where the leds go off, and rebooting doesn't make it reappear. I need to completely shutdown the system and restart it for the vega to reappear.
yet on some systems, it works perfectly fine. same version. same motherboard
In settings before launching turn off the I2C control thingymajig ticker box. Should work fine.