Is it slots 4,5,6,7 again that has the built-in re-drivers on the WRX90?
Those have honestly been a huge pain to deal with in the WRX80, ASUS probably didn’t use very high quality re-drivers. I’m beginning to see the wisdom in packing more MCIO ports closer to the CPU instead of slots. You can drive or re-time the MCIO however you need later.