3DLABS Oxygen 402 - Manual (Page 54)

48 Dynamic Pictures Oxygen 3D Family
The Oxygen 102 (Figure 20) is equipped with a single Oxygen chip and
8 MB of SDRAM. The Oxygen 202 (Figure 21) features two Oxygen
chips operating in parallel, and 16 MB of SDRAM. Finally, the Oxygen
402 (Figure 24) features four Oxygen chips operating in parallel, and 32
MB of SDRAM.
In the case of the Oxygen 102, rendered data from the Oxygen chip is
stored in the 8 MB of SDRAM on the card until it is passed through the
high-end video DAC (Digital to Analog Converter), which supports
color mapping, overlay planes, cursor control, and video clock
generation.
Alternatively, the card’s VGA chip can drive the video display through
a separate port on the video DAC. The VGA chip drives the display
during the boot up process and when operating the system in full-
screen VGA mode (e.g., when playing a VGA-based video game).
In the case of the Oxygen 202 and Oxygen 402, multiple Oxygen chips
operate in parallel, simultaneously rendering to different parts of the
frame buffer. Each Oxygen chip has its own dedicated 8MB of SDRAM.
The unified memory architecture of the Oxygen 3D Family allows
allocation for front buffer, back buffer, Z-buffer, texture memory and
overlays depending on the needs of the user and the desired
applications. Please refer to the
Oxygen Control Panel section on page
24 for more details.