I did a build stream last night and attempted succefully I might add to install the 3080 XC3 Ultra into 2 slot mode. Below is a clip from the stream.
This shows worst case scenario of no custom cables and the XC3 being pushed into the side panel. The fans spin fine without touching the side panel. But any pressure at all and they foul.
But with some tweaks and custom cables. Perhaps removing the backplate we will be good.
Twitch Clip
The long version is that before I put any of the cables in the GPU fit perfectly and there was clearly enough clearance for the fans to spin and it would take alot of bending to get the panel to foul the fans.
The stock SF750 cables are clearly (or at least the way I routed them) are pushing the gpu forward in some way. However that doesnt explain the IO end of the card as there are no cables to push it forward. It is completely possible that the PCIE riser is also pushing the card slightly forward.
Summary.
- The 2.2 slot XC3 will fit. Without modification. But will cause side panel bulge and pressure on the side panels is needed to get the top panel on.
- Side panel bulge hits the shroud first. Which actually gives the fans the clearance they need to spin. (I havent tested deshroud).
- The PCIE is potentially putting pressure on the card. Removing the XC3 back plate would probably fix this (yet to test).
- Custom cables will be a must. With how tight the card is against the side panel you cannot afford any extra pressure pushing the gpu forward.
- I have only turned on the system and havent done a long term test.
- The raise silver 'E' on the fans is actually the tallest part of the card. So if you got desperate you could sand off them off the faces of the fans.
- It does fit and fans do spin. Despite the spec just be prepared to micro manage the build.
**EDIT**
After some more testing the best way to ensure you dont foul the fans on the XC3 ultra is to remove the 'E' stickers from the fans. They are 1mm thick. But its enough to make them the highest point on the cards shroud. By removing them the fans now still recessed in the shroud. Hard to measure but do the guestimate maths in your head. It's well below 1mm of clearance. But the shroud prevents the side panel from hitting the fans even when applying pressure.
I have alot more info in my subreddit thread. So if you want more answers I'd jump over there.