I knew I shouldn't have mentioned the "human-eye" thing, as that wasn't my point at all. My point was that internally the games are probally running well over 100Hz but they're only choosing when to display the image. Updating the display takes CPU cylces that could be used for reading player input, AI & physics caluctaions, syncing multiplayer games, etc... so by only updating the display 30 times a second instead of 60 they get more time to do that stuff(or add more). The first article makes it sound like their slowing the whole game down twice as much, which I highly doubt is the case.