I've upgraded to a Radeon videocard, I think my old one was GeForce something. After upgrading, I started experiencing constant lag in the game (I play on the version 1.15.2, but apparently you can't choose this version in the "affects versions" menu anymore (why?), so I put 1.16.3)
What I expected to happen was...:
I expected the game to run even faster, since I upgraded my videocard and processor.
What actually happened was...:
The game started running much slower and with terrible lag
Because 1.15.2 is an outdated version and no longer supported, the current version is 1.16.3. Please provide a screenshot of your game on that version with the F3 debug screen enabled while the lag is occurring.