980 Ti is painfully gimped on 2C/2T Celeron in DX11, almost fully unleashed by DX12. Once you get to a 4T chip the CPU fails to have ANY further impact whatsoever (<1 FPS difference between i3 and OC i7). This looks like classic GPU-bound behavior, throwing more and more CPU power behind it doesn't increase throughput in the least.
FuryX on the other hand, different story. Huge improvements going from DX11 to DX12 in every case, biggest gains down in Celeron territory where it was obviously the most CPU-bound. Going up in CPU power has a minor impact on DX12 performance, 3% gain from Celeron to i3, basically no change from there until the jump to 4C/8T (5% increase). This says the FuryX is still slightly CPU-bound even at the top end.
Now, looking at CPU impact on FuryX in DX11, it's an even more CPU-bound situation. There's a 20% improvement going from Celeron to i3 and then 3-5% increases with each additional step up (in either speed or core/thread count).
So final conclusion, I'd say FuryX under DX12 is far less CPU-bound than it is under DX11.