A proprietary "smart" technology used by ATi to produce higher fill rates 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.