I just saw this article on AMD FreeSync over at Anandtech:
Using two Toshiba Satellite Click notebooks purchased at retail, without any hardware modifications, AMD demonstrated variable refresh rate technology. According to AMD, there’s been a push to bring variable refresh rate display panels to mobile for a while now in hopes of reducing power consumption (refreshing a display before new content is available wastes power, sort of the same reason we have panel self refresh displays). There’s apparently already a VESA standard for controlling VBLANK intervals. The GPU’s display engine needs to support it, as do the panel and display hardware itself. If all of the components support this spec however, then you can get what appears to be the equivalent of G-Sync without any extra hardware.
AMD doesn’t want to charge for this technology since it’s already a part of a spec that it has implemented (and shouldn’t require a hardware change to those panels that support the spec), hence the current working name “FreeSync”.
So that has me curious. If there’s already a standard for this and if some displays already support it, why all the need for extra hardware on G-Sync monitors?