There's a youtube video available on the Witcher 3, it demo's the game running in Ultra High resolution (Ultra HD). Though this likely is not the final version with extra graphics enhancements, at UHD it certainly does look nice, video after the break.
It looks like the game is being run with a GeForce GTX Titan X with a pretty decent frame-rate, then again, the scene is quite static, buildings and stones flat, but that dense vegetation background with the fog just looks awesome - that's aside from the YT compression and stutters. Have a peek.
