The gt 630m is the mobile version of GT 630, if you're thinking about that. 630m is worse than the desktops 630, and its not a lot better than 610, too.
Also the site I linked doesn't just list system requirements, in fact it doesn't do it at all. It posts an actual benchmark of the game with the Graphics card! That means the AC4 was played on 630m and it was posted there on what settings it got what FPS. As you can see(when you scroll down on the site I linked) the AC4 was run at max low settings at around 23 fps. Most people don't call it playable. I assume you're playing at very low fps, too. Like 20 or under? Well.. :/
And bear in mind that the benchmark was made with 8gb of ram and a lot better CPU than the op has - i7-3720qm