Framebuffer Port Width

• Framebuffer Port width (FPW) measured in pixels

  • Minimum width is one pixel, has RGB values for both front, back framebuffers, Z value, other misc bits

• What is relationship between Fragment Rate, Framebuffer update rate, and Port Width?

Port Width = ceiling (Fragment Rate / Framebuffer Update Rate)

Example:

Desired Fragment Rate = 50Mp/s.

SGRAM access time = 10ns; Mem Update Rate = 50Mhz

Port Width = ceiling (50Mp/s / 50 Mhz ) = 1 pixel

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