This might be a dumb question but...any issues connecting some GPU's directly on the motherboard and some using risers?
Most mining rigs I see in the internet either have all their gpu's connected on the motherboard or all via risers.
I'm planning to use Asus Z370-E for my rig.
only heat the issue but if youre running on water cooled grapics it will be more stable gpu direct on pcie mobo, there is 7 / 8 full pcie mobo and put all together with small case and only gpu blower fan will do the trick, or all liquid cooler will be nice for looking and silent with lower gpu consumption just for hobbies