Originally Posted by
1337Smithy
Indeed, I'm well aware of what vsync does. That's why I said 'also'. It can occur in several situations, but for example with games on the GoldSrc engine when you try to match your in-game fps with your monitor without using vsync (e.g. 144fps with 144Hz) you can induce quite bad screen tearing. It's counter-intuitive, and using vsync caused input lag so that wasn't good either. Changing it to slightly higher or lower than your monitor refresh would often resolve it.