Technical data
added. SM 3.0 is a completely new and very recent
addition, which is supported starting with DirectX
9.0c. Currently, only NVIDIA’s GeForce 6xxx line
of graphics processors can make use of SM 3.0.
If you would like to find out more about the
various DirectX versions and the associated shader
models, you will find lots of relevant information at
the following sites:
It is important to note that you can’t fully assess
the graphics of a game solely by the DirectX ve rs i o n
it uses. For example, D i r ectX 8 shaders can be used
to implement many of the effects used these day s ,
which can bring even cutting-edge graphics pro c e s-
s o r s to their knees. Game deve l o p e r s strive to use as
l ow a DirectX ve rsion as possibl e , so they can target
as large an audience as possibl e . H o w much comput-
ing power a shader will end up needing depends pri-
m a r ily on its complexity. F i n a l l y, it should also be
noted that all cards are dow n wa r d compatibl e.
U p wa r d compatibility is only possible in the case of
ve rtex shaders which can be calculated by the CPU,
and while possibl e, this would be ve r y slow.
Two screenshots of the same scene in the game
FarCry; one on a GeForce 4 Ti (DX8.1) and one
on a GeForce 6800 (DX9).
Bear in mind that although many entry-level
cards are DirectX 9 compliant, they are unable to
deliver playable frame rates due to their low pro-
cessing power (more on this in section #3). In
some cases, the DirectX 9 compliance also refers
only to certain areas.A prime example of this is
Intel’s new i915G integrated graphics chipset.
Although the graphics processor supports Pixel
Shader 2.0 (making it DirectX 9 compliant), it
offloads all vertex shader calculations to the CPU,
increasing CPU load.
OpenGL
After DirectX, OpenGL is the next most popular
3D API. It has existed for far longer than DirectX,
and is available for a large number of operating sys-
tems. DirectX, on the other hand, is confined to
Microsoft platforms.
Like DirectX, OpenGL is constantly being
refined, updated and extended in its capabilities.
Also like DirectX, it is supported by virtually every
current 3D graphics card. Furthermore, the newest
3D features can usually also be implemented in
OpenGL, even if these features have not yet been
defined in the OpenGL standard; these are called
OpenGL extensions. Frequently, graphics chip mak-
ers will offer their own extensions in drivers for
certain effects that can be employed by applications
or games.The two industry heavyweights, ATI and
NVIDIA, offer very good OpenGL support, so
there’s not much to worry about there.Things
aren’t quite as rosy in the case of XGI and S3,
however, which still have some room for improve-
ment in their drivers.
Despite the seeming dominance of DirectX titles,
t h e r e are still many games that are programmed for
O p e n G L . The most well known among these are the
titles published by the Texan game designer id
S o f t wa r e ; m a n y other game deve l -
o p e rs have also licensed 3D game
e n g ines from id to use in their
own softwa r e.The newest and defi-
nitely most demanding OpenGL
game from id is the first pers o n
shooter Doom III. NVIDIA card s
p e r f o r m especially well ru n n i n g
this game, closely followed by AT I ’s
o f f e r i n g s . The game will also ru n
on XGI card s , with some effort
and at reduced quality settings. Fo r
its part , S3 has published a special
Doom III drive r.
Interested readers can find
more information on OpenGL at
http://www.opengl.org/
Other Operating Systems
Things get more complicated for
operating systems other than
M i c rosoft Wi n d ow s . The va r i o u s
c a r d s ’ 3D performance under
L i n ux differs drastically from that in Wi n d ow s . B o t h
THG Graphics Card
Buyers Guide
5
More information on Linux
and graphics cards:
ATI Linux Drivers FAQ
(http://www.ati.com/products/catalyst/l
inux.html)
HOWTO: Installation
Instructions for the ATI
Proprietary Linux Driver
(http://www.ati.com/support/infobase/li
nuxhowto-ati.html)
NVIDIA Linux Advantage PDF
(http://www.nvidia.com/object/LO_2003
0328_6790.html)
NVIDIA Linux Driver Forum @
NVNews
(http://www.nvnews.net/vbulletin/forum
display.php?s=&forumid=14)