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AGP
cards
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| Q1 |
What's the difference between 2D and 3D acceleration?
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| A1 |
Generally, 2D acceleration is targeted
at Windows display applications, it speeds up 2D graphics
(which is consisted by pixel, line and block) in high
resolution, high color depth and refresh rate. 3D acceleration
is targeted at 3D graphics application such as 3D games,
it is very much more complicated than 2D graphics processing.
3D acceleration means some stages of 3D processing (such
as Setup, Texture Mapping, Smoothing, etc) are completed
by graphics controller in the hardware to speed up realistic
3D graphics displayed in real time.
Normally, 3D graphics (e.g.3D game) is processed by the
pipeline stages as below:
(1) Geometry stage ---
a. Tessellation (Objects in Wireframe/Triangles representation)
b. Transformation (Rotation, Scaling, etc)
c. Lighting (Ambient/directional lighting, Ray tracing,
etc)
d. Setup (Projection of 3D objects into 2D planes/screen
coordinate)
(2) Rasterization (Rendering) stage ¨C
a. Visibility (Clipping, culling, Z-buffer comparison,
blending, transparency)
b. Texture Mapping (Wrapping of texture around objects)
c. Shading (Calculation of pixel lighting)
d. Smoothing (Filtering for edge/texture anti-aliasing)
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| Q2 |
What's the difference between EDODRAM,
SDRAM and SGRAM? |
| A2 |
Generally, SDRAM and SGRAM have more high
bandwidth than EDO because of the difference in structure
and access time. And SGRAM has some special command registers
and operations to speed up graphics data accessing, and
SDRAM has not such function. So SGRAM is used by majority
3D graphics cards. |
| Q3 |
What's TV-out, C-video and S-video?
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| A3 |
C-video means Composite-video, it has a
single channel analog signal.
S-video means Special-video, it has two channel analog
signal.
S-video has more stable and sharp video quality than C-video.
TV-out is a video output, it can be connected to the TV
for video display.
Normally, TV-out is a C-video output or a S-video output.
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| Q4 |
What are the AGP bus data
transfer mode |
| A4 |
AGP 1X mode (Sample once per 66MHz CLK,
protocol: Frame#, or PIPE#, or Sideband Addressing, 264MB/Sec
Max Bandwidth)
AGP 2X mode (Sample Twice per 66MHz CLK, protocol support:
PIPE#, or Sideband Addressing, 528MB/Sec Max Bandwidth)
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| Q5 |
What are the advantages of AGP in comparison with
PCI?
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| A5 |
Point to point interface (no device arbitration
needed, cleaner signaling, simple interface)
. 4 times the peak throughput of PCI
. Reduces latency for other devices on the PCI by moving
high-priority graphics from PCI to AGP
. New protocol added than PCI to increase the bus efficiency
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| Q6 |
Why do some AGP cards have similar performance
with PCI cards built-in the same chip?
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| A6 |
Because the graphics controller chip is
not fully complied with AGP specification, and the application
or benchmark software has less data throughput compared
with the bus peak bandwidth. |
| Q7 |
What's the standard software for 3D-performance
measurement?
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| A7 |
'3D WinBench' of ZD Lab is now the only
standard software for 3D-performance measurement, especially
for AGP graphics. The 3D WinMark score can reflect the
performance.
According to ZD Lab, twice the score does not mean twice
performance, but the higher, the better.
Running the test in 'Double buffer' mode to see how the
scenes should look when properly rendered, but without
getting the score. (Double buffer can be changed in the
test setting dialog window). Double buffer mode can test
the 3D-quality effect. |
| Q8 |
What are the advantages of V2200 AGP?
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| A8 |
. RISC processor embedded, hardware triangle,
pixel and fill engine, high 3D performance, 3D quality
also special effect, supports popular games and software
DVD playback.
. Can be used in Windows95 and OSR2,
. Performance does not depend on CPU so much. |
| Q9 |
What influences 3D performance?
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| A9 |
The acceleration ability of the graphics
controller chip influences 3D performance mostly, other
important factors which includes bus bandwidth, video
memory capacity, bandwidth and driver efficiency also
influence 3D performance |
| Q10 |
What are the advantages of Intel 740
? |
| A10 |
Fully AGP compatible, supports AGP 2X,sideband
addressing, DME
. Best 3D performance and quality
. S/W DVD playback support
. Supports popular and new generation 3D tiles. |
| Q11 |
What's AGP memory? |
| A11 |
It's part of the system memory, which is
allocated for AGP graphics used as video memory. |
| Q12 |
Related concept of AGP |
| A12 |
2-D graphics accelerator chip
Often separate integrated circuits are used for displaying
2-D and 3-D graphics, and such graphics cards have separate
2-D and 3-D accelerator chips. Others have the two chips
combined into one.
On-the-fly resolution adjustment and refresh rate control
/ On-the-fly color depth adjustment
On-the-fly adjustments take effect without rebooting
or restarting the operating system's graphical interface.
Color calibration of RGB value
Some graphics card utilities allow you to calibrate
the color value of the signal output from the graphics
card to a setting optimized for the monitor.
Geometry processor chip
For faster rendering, geometry processing can be off-loaded
to a specialized integrated circuit.
Frame buffer memory
The more frame buffer memory the graphics card has,
the larger the screen resolution and the higher the color
depth it supports. 16MB is required for displaying 1,600-by-1,280
at true color in double-buffer mode.
Texture memory
The texture memory is used for rendering the texture
locally on the graphics card, freeing the system I/O bus.
Z-buffer memory
The Z-buffer memory stores the depth value of each
3-D object, which determines whether the object is visible
or hidden behind another object.
Double-buffer color depth
Some graphics systems divide the frame buffer memory
in two and buffer two consecutive frames.
Bilinear/trilinear filtering
Bilinear filtering calculates the color value of a
texel (texture element) applied to a pixel by taking the
weighted average of four adjacent texture elements. This
produces a smoother, more realistic image.
MIP mapping
For optimal performance in realistic 3-D scene display,
the textures of various levels of detail can be applied
to objects in a scene depending on the object's distance
from viewpoint.
Trilinear MIP mapping
Some systems perform linear filtering between texture
maps of varying levels of detail, smoothing the edge transitions
between the different resolution textures. Also, within
a particular texture map, linear filtering is used to
apply texture data to an object's pixel. This method produces
natural-looking 3-D surfaces.
Perspective texture correction at 8 bits and 16 bits
To induce a more accurate sense of distance, the texture
images are distorted in reference to the point of origin.
Anisotropic texture memory
When an object is tilted in respect to the viewplane,
bilinear and trilinear texture filtering do not always
yield the best results. Both methods assume that the texture
elements applied to the image surface are round, but the
projection of texels onto the pixels needs to be elliptical.
Anisotropic texture filtering accounts for this odd positioning
of objects and produces images of superior realism. |
| Q13 |
What is OpenGL? |
| A13 |
OpenGL?is a software interface for applications
to generate interactive 2D and 3D computer graphics. OpenGL
is designed to be independent of operating system, window
system, and hardware operations, and many vendors support
it. OpenGL is available on PCs and workstations.
Since the development of the software and hardware, and
it give software programmers very much convenience, OpenGL
is more and more popular. For exemplar, the newest products
of Autodesk Co. -3D Max 2.0&3D Viz used the OpenGL
as their driver in Win9x and WinNT4.0 at first time.
If you want to know more of OpenGL, just go to the http://www.opengl.org
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| Q14 |
What are direct 3D? |
| A14 |
DirectX is a group of technologies designed
by Microsoft to make Windows-based computers an ideal
platform for running and displaying applications rich
in multimedia elements such as full-color graphics, video,
3D animation, and surround sound. Built directly into
the Windows family of operating systems, DirectX is an
integral part of Windows 98 and Windows NT 5.0, as well
as Internet Explorer 4.0. DirectX components may also
be automatically installed on your system by advanced
multimedia games and applications written for Windows
95.
Direct 3D are an element of DirectX, Designed to enable
world-class game and interactive 3D graphics in Windows,
Direct3D Immediate Mode is an optimized 3D-draw engine
for hardware acceleration and emulation.
Essentially, Direct3D is a drawing interface for 3D hardware.
In the Immediate Mode, Direct3D allows developers to port
games and other high-performance multimedia applications
onto Windows. Its features include switchable z-buffering,
hardware independence, and support for the Intel MMX architecture.
Direct3D Immediate mode also supports drawing primitives
without the uses of execute buffers. |
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