60 hz vs 144hz

Are you talking about the screen refresh rate? If it's going from 60 to 144, you might notice a difference depending on your PC's performance, but depending on your CPU, GPU, memory, and other PC specs, you might not feel much change. It could even make the experience worse. If your PC can generally maintain a decent FPS, the visuals will be smooth, which is good. But if the FPS fluctuates a lot and doesn't stabilize, the stuttering can become noticeable and make aiming harder.

GrizzGolf​ 

You will see a benefit if your PC has enough performance to put out more than 60FPS. If frame pacing seems off above 60FPS, you can use things like V-Sync, G-Sync etc. Thank you. EA_Barry.

If the resolution is the same, there will be no "boost" to performance.

The performance will be the same, but if that performance is already good, you will get a smoother frame rate.

The picture will be much smoother if your pc can output the 144 fps. 

If your PC and pump out more FPS than 60, then you'll have a smoother game play experience, and you might react quicker, when I went from a 60hz, to a 180hz monitor, I started to win more fights in Apex than I use to, and did a lot better that season than i had previously, you won't suddenly become John Battlefield, but you might do better at the game that you where.

If your PC is powerfull enough to put out the 144 FPS stable and constantly, you will notice a huge difference. If you go for a G-Sync or VRR Monitor and you reach something like ~120ish FPS, you will still notice a big difference.