A tribute and update to [Dean2010], if you know what I mean. There's a bunch of "world constants" that directly impact the (low level) system performance limits, and your ability to properly estimate that. Alas, most engineers don't really know those by heart. Worse, they degrade over time, and need regular refreshers. This talk does exactly that: introduces the constants for those who don't yet know that, refreshes them (and introduces a couple that maybe you didn't yet think about) for those who do.