Can I cap the framerate?

Unity Engine
1

Is it possible to have Unity put a hard cap on the framerate, so that no matter how awesome-tacular someone’s system is, I could ensure that the game never renders more than X many frames per second?

Furthermore, I am wondering about the possibility of going in the opposite direction, and force a game to never drop frames. I’m thinking of the old console games that would slow down if the screen got too busy. I know this is very unconventional, but I’m creating an old-school game, and I would like to follow that convention if I can. There are a few other screen effects that I would like to be able to control, knowing that they will be rendered each frame.

2

Application.targetFrameRate sound like the ting you are searching for for the upper limit of the frame rate.

The slowdown in older games was du the CPU side having problem to handle the scene.
maybe messing around with Time.timeScale in case your FPS drops sounds like something you could try.

If the GPU is running out of room there is no way to slow down the game and keep the targetframerate since you still have to render every frame.
Some gamed do dynamically reduce the resolution of the game to keep the frame rate steady in extreme cases, this could be achieved via render textures.