Most games have built in triple buffering these days. However, OpenGL games allow you to force it on, even if it is not programmed into the game. The setting to turn on triple buffering only applies to OpenGL games.
The setting may be useable without v-sync, but it is only useful with v-sync on.
Despite what may have been written in the past, triple buffering has no negative aspect.
Not completely true, but mostly. If you're strained on VRAM, triple buffering is going to tank your performance. The way triple buffering works is by providing 3 rendering surfaces that the game can draw to. It uses a page flipping model to have one buffer on screen while two are eligible for rendering by the application. This allows the application to be able to rending before, during, and after the page flip which helps performance. This obviously costs a bit of VRAM since the surfaces are usually sized equal to the output resolution.