Sorry for the hasty screenshot but I get the "out of memory" error seconds after the RAM peaks at 100%. There was one point here when the integrated GPU briefly bit 100% but Texgen kept going no problem. I'll assign my dedicated GPU (6GB VRAM) to it and try again today but based on this, not sure if it will make any difference.
In the end I ran the Beta version yesterday as usual and didn't give any issues, but I won't give up on 3.0 just yet.