well on my 1080ti's i can get 3.4-3.6sol/w. my cards are hot tho, up to 70C. Im getting about 685-695 sols with 80% tdp. If they were running at <50C, I bet you can get close to 4sol/w
Solo my card ran at 58-60C, though with the other card in the rig it sits at 64C with the 90% TDP. If I stuck my PC in the garage right now I'm sure I'd get fantastic temps since its about -10C or so out.