FRAME RATE AND VSYNC
Performance in games is usually measured in “frames per second” or FPS for short. Frames – still images – are depicted in rapid succession, tricking the human eye into seeing movement. The more frames you see per second, the smoother the image appears to move. This is why a high FPS – or frame rate – is critical for precise and responsive control over your character in any game.
Your FPS depend on how fast your CPU and GPU can render those frames as well as your monitor’s refresh rate which is measured in Hertz (Hz). A 60Hz monitor can only “redraw” the monitor 60 times per second, no matter how good or bad your hardware is. You can technically play with 100+ FPS on an 85Hz monitor, but your screen would only be able to display 85 of those frames every second.
There is a technique called Vertical Synchronization (VSYNC) that is used to ‘sync’ the frames your hardware renders with the refresh rate of your monitor to prevent screen tearing from occuring. Skyrim SE has an inbuilt VSYNC option which has caused performance decreases and other issues for some people (I get horrible screen tearing when I leave it activated) while it works fine for others. For this guide, we will disable it and use the VSYNC function included with the Havok Fix SKSE plugin.
Some higher-end monitors come with G-Sync (for NVIDIA GPUs) or FreeSync (for AMD GPUs) which adapt the refresh rate to the amount of rendered frames. If you own a G-Sync or FreeSync monitor, you might have to experiment a little with your VSYNC settings.
PLAYING AT 60+ FPS
If you’re a Classic Skyrim veteran you may remember that back then we could not unlock our frame rate and play at more than 60FPS because the physics engine would go nuts; it is unfortunately tied to the frame rate, as is standard with the Creation Engine. This can, however, be fixed with a specific INI edit for Skyrim SE so that you can play at up to 240 FPS. 75 FPS appears to be the sweet spot.
Check out this very interesting reddit post for more information and tests.
Please note that the Havok Fix SKSE64 plugin dynamically tweaks that value for you at runtime, so no manual INI tweak is required.