I was going to say you need an extension cable. My first dual 3090 build I had three issues. First was the pcie extension wouldn't support gen4, so I had to change to gen3 in the bios. Second issue was that depending on which slot, you couldn't get x16/x16 and it would drop to x16/x8 unless you had it configured right. Third, I finally gave up and just had the card resting first inside the case and then outside which if fan kicks up, it'll jiggle around, so I had to make some makeshift holder to keep the card sitting there.