pro ws x299 sage ii

Hello, I'm building a system based around the i9-10980XE. I've narrowed the motherboard down to the following two: GIGABYTE X299X AORUS MASTER vs ASUS Pro WS X299 SAGE II Additional Specs: 256 GB RAM 2 x 3090 cards (note each motherboard will allow 1 PCIe space in between the two cards...