Low precision support, almost certainly. SD 1.5 needs almost twice the memory on a 10xx card as on 20xx, because you can't use FP16; a triple bummer, since that

Low precision support, almost certainly. SD 1.5 needs almost twice the memory on a 10xx card as on 20xx, because you can't use FP16; a triple bummer, since that makes it even slower (memory bandwidth!) and you don't have as much to begin with.