> 3) I'm leaning towards a Supermicro H12SSL-i motherboard which I've seen people run quad A5000's on without any hassle. Proper PCIe x16 slots spaces 2x apart,

> 3) I'm leaning towards a Supermicro H12SSL-i motherboard which I've seen people run quad A5000's on without any hassle. Proper PCIe x16 slots spaces 2x apart, and i'd likely be watercooling all 4 cards together in a 2-slot spacing or installing MSI turbo heatsinks with blower fans / server rack style for 2 slot cooling. I had a 3x3090 rig. 2 of them are fried. 2 of them had two sided Bykski blocks (would never fit next to each others 2 slot apart, water header block with 90 degree corner plumbing is full 4x slot size minimum). 3090 are notorious for their vram chips, on the backside, failing due to insufficient cooling. Also, 1kW of heat needs to be evacuated. Few hours of full power can easily heat up neighbouring rooms as well.