According to official specifications for the RTX 3090, it's 12.32" long. However, as you can see in the picture below, my tower doesn't quite have that amount of clearance. I'm thinking that perhaps I can insert it into one of the lower PCIe slots so that it can (hopefully) protrude into one of the hard-drive bays and therefore fit into the case, but that's assuming that I can even somehow maneuver it into the case's opening. Do you think it's possible? If not, I'd seriously just buy a new case, because I really want the 3090. Also, I'm planning on building a new PC next year when DDR5 is released; hence, the new case (and the 3090) could be re-purposed for that build.
Picture:
Link
UPDATE:
Apparently I can individually remove the hard drive cages in my computer case to allow more room for GPUs; removing a hard drive cage creates a maximum of 428mm of space for a GPU, which is more than enough for the RTX 3090, which is 315mm long. So, I'll just remove the hard drive cage that's level with the top PCIE-slot on my mother board, and move the hard drive that's in it to the bottom hard drive cage, since the two above it are occupied.