ASUS 3DP-V500TX
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A. REGISTRY & DMA VARIABLES
A. REGISTR
Y
& DMA
Registry V
ariables
This variable is read every time a 3D context is created. Thus it is not necessary to
reboot the machine for a change to take effect. Changing this variable has no effect
on any already running 3D applications. The installation default is 5.
This variable can have considerable 3D performance implications. 2 is usually ideal
for single-buffered applications and 5 seems well suited to double-buffered applica-
tions.
GlintDMA.AllocateCached: The driver automatically determines whether the DMA
buffers can be allocated as cached or uncached. Setting this variable to zero forces
buffers to be uncached; setting it to 1 forces buffers to be cached. It is not recom-
mended that this variable be created or modified. The default installation does not
create this variable. You must reboot for changes in this variable to take effect.
This variable should not be defined on Alpha platforms as using uncached DMA
buffers has undefined results on these machines.
GlintDMA.LatencyTimer: This variable sets the PCI latency timer for the GLINT
chip. This determines the maximum number of PCI cycles that GLINT can hold
onto the PCI bus while performing DMA once the bus grant has been removed. It is
not recommended that this variable be modified. You must reboot for changes in this
variable to take effect.
3DInterfaceBuffer.SizeLongs: This defines the length of the shared memory buffer
used by the OpenGL DLL to communicate with the driver. The length is specified in
DWORDS. The installation default is 0x2000 (32KB).
3D Double Buffering Control
DoubleBuffer.NumberOfBuffers: This specifies the total number of screen-sized
buffers to be allocated from VRAM by the driver. One buffer is always allocated for
the main, displayed screen. If this variable exists and is greater or equal to 2 then a
second off-screen buffer is allocated for use by the 3D extension (values > 2 are
reserved for future use). Any VRAM remaining after allocation of the screen-sized
buffers is available for use by the display driver for pattern cache and off-screen
bitmaps. The installation default is 2. You must reboot for changes in this variable
to take effect.
DoubleBuffer.MultiColorSpace: Setting this variable to 1, specifies that the sys-
tem lock on the double buffering token should be ignored. This will allow applica-
tions such as the ProEngineer CAD package which creates multiple double buffered
rendering contexts, but only ever display one double buffered window to use color
space double buffering. The caveat is that if a second double buffered application is
started then it will ignore the system lock resulting in flickering or incorrect pictures
being displayed, as there will be no arbitration between the applications, of when
the swapbuffers command (which affects the whole screen) is executed. This is not
created at installation by default which is the same as setting it to 0, meaning that the
lock is in force. You must reboot for changes in this variable to take effect.
