Good to know thank you.
I just ran spi32m @ 230 bclk with VTT set to 1.5v and reading 1.28 @ idle and PCIE @ only 110MHz.
It froze up when I increased it another 2MHz. Not sure what was the cause yet.
Memory was @ 900 something with 8-8-8, going to try 8-9-8, but probably need more VTT or PCIE to get higher than 230 bclk.
EDIT: looks like I'll need to get some LN2 for the lengthy benches, or learn DICE.