Is that a recent development? One of Quadro's feature over GTX was/is 10-bit output. No way around it if you're using a 10-bit monitor like EIZO ColorEdge or whatever.

My GTX on Windows also claims to output 10 bits. From some playing around in Photoshop, it seems like the monitor I have does not actually use the extra data. (It asks for it, but either doesn't receive it, or doesn't process it properly.)