Aragorn said
Ticks Per Second. There is SUPPOSED to be 20 ticks in a second. Any less and you start getting lag(furnaces and crops not operating/growing as fast as they are supposed to. Low enough and you can even get block lag. In 1.8 chunk generation is massively optimized, thus TPS improvements. And rendering is multithreaded, so if your processor has at least two cores, you will notice a massive FPS boost.
Well, this will be wide spread loved.