Charlie from The Inquirer heard NVIDIA may have to delay the G84 and G86 GPUs. It's possible that the firm will go on and release the chips on April 17th but if that's the case it may be wise to avoid them as the first parts had a nasty bug, he says:
The problem as we understand it is the 2D modes are not clocked down to where they should be. NV has a 2D clock that is a lot lower than the 3D clock which saves battery power and in general, makes things run cooler and quieter.
The bug we are told prevents them from clocking 2D down to a level lower than 3D increasing power substantially. Basically, when the parts should be clocked down in 2D where they spend most of their life, they instead run flat out.
Before you get one of these in a laptop or SFF machine, make sure this is not happening in the ones you buy.