Smoothvision is ATI's newest method of instituting anti-aliasing.
The way in which it differs from traditional anti-aliasing is, again falling
in with the current trend, to allow programmability. Smoothvision is a multi-sampling
AA method, meaning it renders four frames of the same scene then averages out
colour values from selected points of each pixel to be Anti-aliased. It
allows developers to either program or randomize the pattern of sample points
within each pixel. This should lead to more 'natural' looking blending between
the edges of a model and the background scene.
As well as the
three new technologies, the 8500 chip also offers enhanced versions of several
of the original Radeon's flagship features.
is a combination of three technologies aimed at conserving memory bandwidth
inside the graphics card. Hierarchical Z checks whether each
pixel to be rendered will actually be visible in the final frame, referencing
the Z-buffer (a memory area which stores the depth, or Z value of each pixel
to be rendered) to find the information. What sets this apart from other graphics
chipsets is that the Z-buffer check is performed before the pixel is rendered, and pixels that will not
be visible are discarded, thus conserving bandwidth. Most graphical chipsets
will texture and shade a pixel before checking it against the Z-buffer.
Z-compression compresses the information
stored in the Z-buffer, saving more bandwidth, and finally, Fast Z-clear
ATI's method of clearing the z-buffer quickly after a frame has been rendered.
The 8500's HyperZ II is capable of discarding
more unnecessary pixels per clock cycle, compressing Z-buffer data more efficiently
and generally doing more Hyper Z things... you get the picture. Not overly different,
just enhanced for the new chip. Same thing with the Charisma Engine
II (nice name...) which is the transform and lighting engine that works
along with the Smartshader to draw, manipulate and light triangles prior to
Pixel Tapestry II is
the 8500's pixel rendering engine, and as noted above, has full support for
DirectX 8.1 and the ability to draw up to 6 pixels in a single rendering pass.
Other interesting things include support for ATI's Hydravision technology, first seen earlier
this year in the Radeon VE. This is a flexible implementation of dual monitor
support, with added TV-out ability, allowing dual CRT monitors with independent
displays and resolutions, or one CRT and one Digital flat panel display, or a
CRT or flat panel plus a TV set. You can also set up the TV as a third monitor,
cloning one of the other two displays.
Video Immersion II is a combination of ATI's historically excellent hardware MPEG-2/DVD
decoding with improved de-interlacing for video output. This should work hand in
hand with the Hydravision feature to allow much higher quality video for DVD
viewing and gaming on television sets.
in all, the Radeon 8500 appears to be a promising competitor for
the Geforce3... However a lot of its potential success rests on how software developers take to the
new features it offers. Truform could become a standard if it works well,
and its ability to be patched into current games means that its adoption could be
quite quick. The support for pixel shader 1.4 spec., on the other hand, seems less likely to be
a hit. It is unlikely that we will see many games being released specifically for DirectX 8.1
until next year, by which time no doubt the next wave of
Nvidia and ATI chips will be almost upon us, making the feature pretty much
irrelevant as a selling point.
Without the success of these two technologies, the 8500 will have to go head to
head with the GF3 on pure speed alone, which it may well be able to do. A lot
will depend on drivers, of course, and ATI has had a few problems in this area
before. The 8500 should be released in late September/early October, with the
price point apparently set a little bit higher than the average Geforce 3 card's
introductory price, but not significantly.