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HSync
HSync
Monitor
Connector
RGB
Figure 6-2. GMCH Integrated Graphics Subsystem
The integrated graphics controller includes special enhancements for 2D operations. Motion
compensation logic is included to improve performance during software decoding of MPEG2
video. Hardware cursor and overlay engines relieve software processing and provide independent
gamma correction, saturation, and brightness control. The 230-MHz RAMDAC can support a
variable-scan rate monitor up to a maximum resolution of 1600 x 1200 with 256 colors. Video
BIOS for the controller is held in the system BIOS ROM and copied into system memory at
runtime for maximum performance.
On Pentium III-based systems, four megabytes of display cache is included that enhances 2D and
3D performance up to 30%. The local display cache allows the graphics controller to
simultaneously render graphics to the Z-buffer (in the display cache) while processing textures in a
portion of system memory, increasing 3D performance substantially. The integrated graphics
controller uses a specific amount of system memory. This memory is allocated as follows:
Video BIOS – 512 or 1024 kilobytes. An OS report of available system memory will be the total
amount installed LESS this amount.
Graphics Memory – Prior to the PV 4.x driver being loaded, the graphics memory will be one
megabyte for supporting standard VGA modes. After driver load, memory allocation will be set by
the Dynamic Video Memory Technology (DVMT) for rendering, Z-buffering, and displaying
according to need and total system memory availability. The following table indicates the amount
of memory allocated depending on operating system and memory availability.
OS Type and
Sys. Mem. Amount
Windows 98 w/32 MB
Windows 98 w/64 MB
Windows 98 w/128 MB
Windows NT 4.0 w/64 MB
Windows NT 4.0 w/128 MB
Windows 2000 w/64 MB
Windows 2000 w/128 MB
82810E or 82815 GMCH
Graphics Controller
3D
Engine
2D
Pipelined
Engine
Preprocessor
RAM
DAC
Total Graphics Memory
w/o 4-MB Display Cache
6 MB
10 MB
10 MB
9 MB
9 MB
9 MB
10 MB
Compaq iPAQ Series of Desktop Personal Computers
Second Edition - February 2001
Technical Reference Guide
FSB I/F &
SDRAM
Cntlr.
AGP
I/F
Display Cache
Total Graphics Memory
w/ 4-MB Display Cache
9 MB
12 MB
12 MB
12 MB
12 MB
12 MB
12 MB
6-3
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