This comment is very incorrect. ROPs are not "GPU cores", and this term is not exclusive to Nvidia, AMD and Intel GPUs have ROPs too.

The GPU equivalent to CPU cores are the stream processors inside each SM (Nvidia) or CU (AMD), of which GPUs have thousands of. Those are the general-purpose, programmable processing units that run shader code.

ROPs are completely different. It's a separate structure inside a GPU that is specialized in one task. ROPs take a 3D world in vector (infinite resolution) format, and convert that vector scene into a grid of squares (i.e. pixels) in order for it to become the kind of data that can be displayed by our screens, and sampling colors inside those squares to determine what the final pixel color should be. ROPs only do that, they can't do anything else, they don't run arbitrary code like GPU stream processors and CPU cores do. They would be analogue to, say, a media encode engine in a CPU, a specialized block separate from the cores that only does one thing.

Shame on everyone who upvoted this blatantly wrong info. This subreddit is supposed to be better than this.

Also u/AuroraFireflash here's the correct answer for you.