Unlike the RTX 3080 graphics card, the fat brother occupies 3 slots on a motherboard. A photograph from Chiphell appears to show RTX 3090 is a mid-tower case with ASUS Prime motherboard installed. It looks like the sagging problem has been resolved by supporting the card on an SSD cage. A dual 8-pin to single 12-pin power adapter is also pictured feeding the power to the card.The location of the 12-pin PCIe power connector doesn't seem to be ideal though. As you can see on the photo below, it makes cable management really hard.