Here are some tests:

1.1. Playing in windowed mode with VSync disabled, no frame limit and driver-side Triple Buffering disabled will result in ~100-150 FPS with tearing effects.
1.2. Enabling VSync will result in 60 FPS and the tearing does stop.
1.3. Setting the frame limit to 50 will result in 50 FPS with no tearing.
1.3.1 This could already be a bug as either there should be tearing effects with 50 FPS or the FPS should go down to 30.

2.1. Playing in windowed mode with VSync disabled, no frame limit and driver-side Triple Buffering enabled will result in ~100-150 FPS with tearing effects.
2.2. Enabling VSync will result in 60 FPS and the tearing does stop.
2.3. Setting the frame limit to 50 will result in 50 FPS with tearing.
2.3.1. Due to Triple Buffering the 50 FPS are here correct but the tearing should not appear.

Also I'm noticing heavy performance impacts on input as soon as Minecraft is minimized if Triple Buffering is enabled.