According to Bit-Tech,  Nvidia is adding some form of DRM to back up its existing terms and conditions forbidding such activity.

Nvidia is worried that people are seeing that bundled games aren't a mere bonus but a discount waiting to happen. You can get the game codes and trade them to flog them on.

If buyers buy multiple GPUs for an SLI/CrossFire setup they will get three copies of a game and selling them off will help reduce the cost of getting such an expensive rig.

While Nvidia expressly banned any selling on in the terms and conditions, it's a rule that has never been enforced - up to now.

Now Nvidia is the industry lead in punishing its customers and blocking the sale or trade of bundled game codes.

Nvidia is doing this by requiring the user to have the GeForce Experience software installed and running. Next the person doing the redeeming will need to have a graphics card equal to or better than the one with which the game was bundled.

There are also a few conditions which will hack off those poor customers who bought the GPU and did not want to sell the game. Firstly they have to set the game up in the same region as the purchase. This basically kills off buying a card in another part of the world or online.

Nvidia has confirmed that the first locked down games are (ironically) For Honor and Tom Clancy's Ghost Recon: Wildlands. It will be interesting to see how much of a backlash this sort of thing will create.