Vsync being turned on automatically caps the fps at 30. Once you turn it off, you uncap your fps.

Unfortunately, this is not where this guide ends, because you do need your fps capped. At higher fps, some aspects of the game break - QTEs, physics, menus and maybe some other stuff as well, not even mentioning that your graphics card will be under much more strain.

For me, with Vsync on, heat of my GPU is generally around 35C, with Vsync turned off, my GPU's fans start sounding as if they're getting ready for take off and heat rises rapidly to 60C and above.
To fix these issues, proceed to step 2.

To do this you have to do the following:

1. Open your NVIDIA control panel (sorry, AMD users, but I don't know what your alternative would be)
   
2. After you've opened it, go to Manage 3D Settings tab
   
3. Choose the Program Settings tab
   
4. Select Dead Space 2 (deadspace2.exe)
   
5. Scroll down to the Max Frame Rate setting and set it to 60 (or any value you're comfortable with, usually your monitor's refresh rate)
   
6. While you're still here, you can also turn on the Vsync in the same 3d Settings tab (but don't turn the Vsync on in the game's Video settings menu)

Congratulations, now your game is capped at 60 fps, so you should avoid (almost) all problems caused by running the game at high fps.
There are still two problems that need to be fixed, but, fortunately, they both have the same solution.
Let's move on to step 3.

The 2 remaining problems I alluded to in step 2 are:

1. The aforementioned additional strain on the GPU
   
2. Aiming sensitivity is dependend on the fps, so, at different fps, the sensitivity will be different. While that's not really a problem with 60 fps cap on modern PCs, weirdly enough, the existing fix for the mouse also (at least in my experience) fixes the GPU heating up problem. It also fixes some other issues with mouse aiming, so it's a good idea to install it anyway.

So, in order to solve two issues with one fix, all you have to do is download the Dead Space 2 mouse fix from here:
https://community.pcgamingwiki.com/files/file/976-dead-space-2-mouse-fix/

Once you've downloaded it, you need simply extract the dinput8.dll into the games' main folder.

But here's a little warning: according to PCGamingWiki, it does crash your game when you play in multiplayer as necromorph, so, if you're gonna be playing multiplayer, delete it before doing so.

With all this being done, you can enjoy playing the game at silky-smooth 60 fps, the aiming will feel better and you won't have to be annoyed by your GPU's fans trying to break the sound barrier.