"smart" technology used by ATi
to produce higher fill rate
s on their Radeon
series of video cards
In contrast, cards like the Geforce2 GTS attempt to increase their fill rate by brute force. This is because they render every pixel on a screen, whether or not it will be visible in the final frame. This is because a pixel is rendered before its Z-buffer position is checked.
HyperZ checks whether a pixel will be visible, by checking its positition within the Z-buffer. If visible, the pixel is sent to the rendering pipeline. If it won't be visible, the pixel is immediately discarded.
HyperZ also uses z-compression, to reduce time spent loading the Z-buffer, and a proprietary method of clearing the Z-buffer, instead of writing zeroes to every register like most other cards.
nVidia's next-generation card, the NV20 is rumored to use a similar technology. That would truly be godlike.