Now that AMD has released its Radeon RX 470 and Radeon RX 460, the ball is back in Nvidia's court, and some insider photos of a press briefing or similar event obtained by Chinese site IT House might give us some insight about how the green team will respond. If the leaked photos are correct, Nvidia will offer a purported "GTX 1060 3GB." This card doesn't just lose half its RAM over the existing GTX 1060, though—the photo from the event shows that the card could have 1152 SPs, down from 1280 on the 6GB card.
The full GP106 die on the GTX 1060 spreads its stream processors over 10 SM units, so the loss of 128 of those SPs most likely points to the disabling of one SM on the card (or the equivalent across multiple SMs). If Nvidia does take the world's smallest chainsaw to GP106, this 3GB card would likely lose some texturing capability, as well. IT House's source suggests the card's specs will otherwise be identical to the 6GB version's. We'll just have to wait and see what breaks cover when Nvidia's inevitable response arrives.